ISO/FDIS 6426-2

ISO /TC 114/SC 9
Secretariat: AFNOR
Date: 2025-10-07xx
Horological vocabulary — —
Part 2:
Technical and commercial definitions
Vocabulaire horloger —
Partie 2: Définitions technico-commerciales
FDIS stage
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ii
Contents
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Terms and related time . 1
5 Terms and related time-measuring instruments . 1
6 Terms and related essential devices and parts . 4
6.1 Power supply . 4
6.2 Time base . 5
6.3 Display . 6
7 Terms and definitions related to functions (see Annex A) . 7
7.1 Display of time . 7
7.2 Chronograph . 7
7.3 Alarm . 7
7.4 Calendar . 8
7.5 Other functions . 9
7.6 Additional functions for smartwatches . 11
8 Terms and related components . 12
8.1 Movement components . 12
8.2 Casing components . 15
9 Terms and accuracy of a time-measuring instrument . 16
Annex A (informative) Functions, indications and additional devices related to those functions20
Bibliography . 22
Index . 23

iii
8.1 Additional devices specific to smartwatches. Erreur ! Signet non défini.

iv
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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This document was prepared by Technical Committee ISO/TC 114, Horology, Subcommittee SC 9, Technical
definitions.
This third edition cancels and replaces the second edition (ISO 6426-2:2002), which has been technically
revised. It also incorporates the Amendment ISO 6426-2:2002/Amd.1:2012 and theTechnical Corrigendum
ISO 6426-2:2002/Cor.1:2003.
The main changes compared to the previous edition are as follows:
— — some new definitions were added;
— — some definitions were modified;
— — the standard’s structure was modified;
— — Table 1 was moved as a new Annex Aan Annex.
A list of all parts in the ISO 6426 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
Introduction
This document gives technical and commercial definitions; ISO 6426-1 gives technical and scientific
definitions, mainly relating to the rate of the time-measuring instrument.
The definitions given in this document, intended more particularly for the general public, have been simplified,
especially with regard to terms concerning the rate of a time-measuring instrument.
Where there is ambiguity, it is advisable to refer to the definitions of the corresponding terms in
ISO6426ISO 6426-1, which are more detailed.
Some commons terms, the definitions of which do not give rise to any confusion, and which occur in other
specialized documents, have not been included in this document.
vi
Horological vocabulary — Part 2: Technical and commercial
definition —
Part 2:
Technical and commercial definitions
1 Scope
This document defines the principal technical and commercial terms used in the horological industry.
The terms and definitions apply to time-measuring instruments and related devices.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
4 Terms and related time
4.1 4.1
time
undefined medium in which existing objects appear to develop irreversibly in the changes which they
undergo, and in which events and phenomena appear to occur in their succession
Note 1 to entry: To this medium corresponds a quantity, t, allowing, in a time scale, the chronological filing of events.
4.2 4.2
date
instant in a time scale
Note 1 to entry: In current use, the notation of this term stands for the indication of the year, month, day of the week
and day of the month.
5 Terms and related time-measuring instruments
5.1 5.1
time-measuring instrument
instrument indicating the time of day or measuring a duration, separately or simultaneously
5.2 5.2
timekeeping instrument
time-measuring instrument, indicating the time of day
5.3 5.3
counter
time-measuring instrument, measuring durations
Note 1 to entry: It does not indicate the time of day.
5.4 5.4
programmable time counter
time-measuring instrument fitted with one or more devices permitting control of operations at predetermined
intervals of time
5.5 5.5
programmable timekeeping instrument
programmable time counter which incorporates the functions of a timekeeping instrument
5.6 5.6
watch
timekeeping instrument designed to be worn and to function in all position
5.7 5.7
stopwatch
portable time counter allowing measurement of durations
5.8 5.8
clock
time-keepingtimekeeping instrument that is not intended to be worn, but rather used in a certain position
5.9 5.9
mechanical timekeeping instrument
timekeeping instrument of which the following main components are exclusively mechanical: driving energy,
oscillating device and its maintenance, time display
5.10 5.10
electric timekeeping instrument
timekeeping instrument having a source of electrical energy and a system for electromechanical maintenance
of the oscillating device (having a mechanical contactor, that is, complete absence of any electronic control of
the oscillating device)
5.11
5.11
solar cell timekeeping instrument
timekeeping instrument that utilizes light energy as a source of electrical power
5.115.12 5.12
electronic timekeeping instrument
timekeeping instrument having an oscillating device maintained by electronic control
5.125.13 5.13
spring balance timekeeping instrument
timekeeping instrument whose time base comprises a spring balance oscillating device
5.135.14 5.14
quartz timekeeping instrument
timekeeping instrument whose time base comprises a quartz oscillating device
5.145.15 5.15
tuning fork timekeeping instrument
timekeeping instrument whose time base comprises a metal tuning fork oscillating device maintained
electromagnetically
5.155.16 5.16
digital quartz timekeeping instrument
timekeeping instrument having a quartz time base in which the display is digital
5.165.17 5.17
analogue quartz timekeeping instrument
timekeeping instrument having a quartz time base in which the display is by a dial and hands
5.175.18 5.18
analogue and digital quartz timekeeping instrument
quartz based timekeeping instrument having a combination of analogue (hands) and digital
(numerals)displays
5.185.19 5.19
timekeeping instrument with small seconds hand
timekeeping instrument with a seconds hand whose axis is offset from the hour and minute axis
5.195.20 5.20
multifunction timekeeping instrument
timekeeping instrument having other functions in addition to those indicating hour, minute, second, date and
day
5.205.21 5.21
radio-controlled timekeeping instrument
timekeeping instrument which can receive standard time signal and automatically regulate time and calendar
according to the received signal
5.215.22 5.22
skeleton watch
watch in which it is possible to observe the movement through a transparent exterior, the movement having
hollowed parts or transparent parts allowing the mechanism to be viewed
5.225.23 5.23
tourbillon watch
watch including a turning cage which carries all the parts of the escapement and, in its centre, the regulator
element (balance with hair spring) as a time base
Note 1 to entry: The escapement pinion is carried around the fixed fourth wheel, which in this case is the seconds’
wheel. The cage generally turns one revolution per minute, and it minimizes the vertical positional timing errors whilst
it turns.
5.235.24 5.24
carrousel watch
watch including a device similar to a tourbillon but in which the cage is driven by the third wheel
5.245.25 5.25
chronograph
timekeeping instrument comprising a time counter allowing measurement and display of time intervals
independently of keeping and indicating the time of day
Note 1
...