"art or process of ascending in and managing a balloon," 1784, verbal noun from balloon (v.).
"a substance produced by a chemical process, a chemical agent," 1747, from chemical (adj.). Related: Chemicals.
"action or process of making or being operative," 1906, noun of action from activate (v.).
1660s, "process of suckling an infant," from French lactation, from Late Latin lactationem (nominative lactatio) "a suckling," noun of action from past-participle stem of lactare "to suckle," from lac (genitive lactis) "milk" (from PIE root *g(a)lag- "milk"). Meaning "process of secreting milk from the breasts" first recorded 1857. Related: Lactational.
"fact or process of reabsorption, retrogressive absorption," 1670s, noun of action from resorb.