Might want to slow down with the laughing at others. The words "primary," "secondary," and "tertiary" have been in use in non-military contexts for centuries.
The online etymology dictionary (etymonline) is the internet's go-to source for quick and reliable accounts of the origin and history of English words, phrases, and idioms.
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early 15c.,
primarie, "earliest, most basic, first in time or sequence;" 1560s, "first or highest in rank or importance," from Latin
primarius "of the first rank, chief, principal, excellent," from
primus "first" (see
prime (adj.)).
The meaning "first or lowest in order of growth or development; elementary, preparatory" is from c. 1800, first in education;
primary school is attested by 1793 in translations from French, from
école primaire.
Primary color is attested from 1610s (at first the seven of the spectrum, later the three pigments from which the others can be made). Related:
Primarily.
secondary(adj.)
late 14c.,
secondarie, "belonging to the second class; not chief or principal; second in importance or authority; of a lesser quality or worth; subordinate to something else, depending upon the action of primary qualities," from Old French
secondaireand directly from Latin
secundarius "pertaining to the second class, inferior," from
secundus (see
second (adj.)).
Opposed to
primary (adj.) or
principal (adj.). Of colors, under the old theory, from 1831; in reference to schools or education, from 1809. Of characteristics peculiar to one sex but not necessary for reproduction, from 1780. Related:
Secondarily; secondariness.
As a noun from mid-15c. as "thing or place of secondary importance or which is dependent on a primary;" 1590s as "a delegate or deputy." The U.S. football sense of "defensive backfield" is by 1955.
tertiary(adj.)
1650s, "of the third order, rank, degree, etc.," from Latin
tertiarius "of or pertaining to a third," from
tertius "third, a third," from root of
tres "three" (see
three).
The geological sense (with capital
T-) in reference to the era between the Mesozoic and the
Quaternary is attested from 1794, after Italian
terziari, used in this sense 1760 by Italian geologist Giovanni Arduino (1714-1795). It dates from a very early period in geology and a division of rocks into
Primary,
Secondary (the older name for the Mesozoic) and
Tertiary based on resemblance of fossil shells to populations of living seas. In early use in England it meant vaguely "the Formations above the Chalk."