lactate v.

1790, "procured from milk," in the chemical name lactic acid, which is so called because it was obtained from sour milk. From French lactique, from Latin lactis, genitive of lac "milk" (from PIE root *g(a)lag- "milk.") + French -ique (see -ic).

word-forming element used in forming nouns from Latin words ending in -atus, -atum (such as estate, primate, senate). Those that came to English via French often arrived with -at, but an -e was added after c. 1400 to indicate the long vowel. The suffix also can mark adjectives formed from Latin past participles in -atus, -ata (such as desolate, moderate, separate); again, they often were adopted in Middle English as -at, with an -e appended after c. 1400.