In any situation where a value has to be supplied by the user, the user may be saved this trouble by having the software supply a particular fixed value. That is, if the user does not explicitly specify a value, the program-supplied value is used, and is known as a "default value" — it is used in default of the user explicitly supplying a different value. This is useful if there is a particular value which users are expected to want to use on a large proportion of occasions.
An example would be the default filename when saving a file.
My preferred term for "default value" would be "luach éagmaise", or in Scotland, "luach eugmhais". (Ó Dónaill glosses "éagmais" as absence, lack or want; déanamh in éagmais ruda — to do without something).
At first, the official term was "loicrogha" (TR 110, for "default option"). This does not sit well with my understanding of "loic", which is to refuse to do something which we are meant to do, as to default in repaying a loan. In the context of a machine, "loic" suggests breaking down or ceasing to function.
Other terms have been suggested, all preferable to "loicrogha", but all differing slightly in meaning from "default value". They include "luach caighdeánach", "luach réamhsocraithe" and "gnáthluach". None of these has the clear implication of a value which is used when no other is nominated. On "caighdeánach", it may be pointed out that a word processor, for example, may have many "standard templates", but only one of them (at a time) can be the "default template". Also, "luach caighdeánach" might run some risk of confusion with unrelated ideas so named, such as that of a standard value from a normal distribution in statistics; or even with the standard form of a number in arithmetic.
Currently the official term is "luach/rogha
réamhshocraithe" or "réamhshocrú" (FR 209).
The term is also used of the "default settings" of a piece of hardware or software. These may be the settings chosen by the manufacturer, or they may have been altered by someone more local such as a lab administrator. At all events, they are the settings which the end user inherits on each occasion when he does not specify otherwise. We might have such terms as "manufacturer's default values: luachanna éagmaise an deántóra", but conciseness would suggest shortening these terms; in English "values" is the easiest thing to remove, while in Irish, "default" is the easiest to remove. Thus "luachanna an deántóra: manufacturer's defaults", "luachanna na háite: local defaults", "luachanna an úinéara: owner's defaults", "luachanna pearsanta: personal defaults", etc.