-cide

1.
a learned borrowing from Latin meaning “killer,” “act of killing,” used in the formation of compound words:
pesticide, homicide.
Origin
late Middle English < Latin -cīda killer, -cīdium act of killing, derivatives of caedere to cut down, kill (in compounds -cīdere)
British Dictionary definitions for -cide

-cide

combining form
1.
indicating a person or thing that kills: insecticide
2.
indicating a killing; murder: homicide
Derived Forms
-cidal, combining_form:in_adjective
Word Origin
from Latin -cīda (agent), -cīdium (act), from caedere to kill
Word Origin and History for -cide

word-forming element meaning "killer," from French -cide, from Latin -cida "cutter, killer, slayer," from -cidere, comb. form of caedere "to strike down, chop, beat, hew, fell, slay," from PIE *kae-id-, from root *(s)k(h)ai- "to strike" (Pokorny, not in Watkins; cf. Sanskrit skhidati "beats, tears," Lithuanian kaisti "shave," German heien "beat"). For Latin vowel change, see acquisition. The element also can represent "killing," from French -cide, from Latin -cidium "a cutting, a killing."

-cide in Medicine

-cide suff.

  1. Killer: bactericide.

  2. Act of killing: suicide.

-cide in Science
-cide  
A suffix that means "a killer of." It is used to form the names of chemicals that kill a specified organism, such as pesticide, a chemical that kills pests.