Where does “positive lookahead” come from?

positive lookahead (English) comes from English lookahead, from English ahead, from English head, from English -y, from Middle English -y, from Old English -iġ, from Proto-West Germanic -g, from Proto-Germanic -gaz — -y, -ic.

positive lookahead (English): The analysis of the subsequent characters presence before the regular expression is matched (symbol:?=)

Definitions

  1. The analysis of the subsequent characters presence before the regular expression is matched (symbol:?=)

Ancestry of “positive lookahead”, step by step

positive lookahead traces back through two separate lines of ancestry.

via English lookahead

StepLanguageWordMeaning
1EnglishlookaheadThe analysis in advance of subsequent decisions...
2EnglishaheadIn or to the front; in advance; onward; In the...
3EnglishheadThe part of the body of an animal or human which...
4English-yAdded to nouns and adjectives to form adjectives...
5Middle English-yDesignates an adjective, in many cases formed by...
6Old English-iġ-y, -ic
7Proto-West Germanic-gForms adjectives from nouns and verbs with a...
8Proto-Germanic-gaz-y
9Proto-Indo-European-ḱos-y, -ic

via English positive

StepLanguageWordMeaning
1EnglishpositiveNot negative or neutral; Formally laid down;...
2Old Frenchpositif
3Latinposītivuspositive
4Latinpōnōto place; to put; to lay
5Proto-Italicpoznō
6Proto-Italicpozinō
7Proto-Italicsinō
Every word from Proto-Indo-European -ḱosEvery word from English -yEvery word from Old English -iġ