【Antiseptic】 , 【germicide】 , bactéricide and  【disinfectant】 all denote an agent that interferes with the growth and activity of microorganisms.

An 【antiseptic】 is an agent that prevents or arrests the growth and activity of microorganisms, especially disease germs, without necessarily killing them. The word is used especially of substances mild enough to be used on living tissue.

【Germicide】 is used of an agent that kills microorganisms and especially disease germs. It is commonly applied to strong chemicals which cannot safely be used on living tissues.

A bactéricide is a 【germicide】 that destroys all kinds of bacteria (but does not necessarily kill bacterial spores).

A 【disinfectant】 is an agent that frees from infection and especially a chemical 【germicide】 used to kill disease germs and other harmful microorganisms in sources of infection (as drains, sickrooms, clothing, bedding, laboratories, and stables).

【Disinfectant】 may be used of substances (as chloride of lime) which destroy disagreeable odors by interfering with the activity of the bacteria causing putrefaction.

The same distinctions hold for the corresponding adjectives 【antiseptic】 , germicidal, bactericidal, 【disinfectant】 .