1.Today's Words

1) de-: active word-forming element in English and in many words inherited from French and Latin, from Latin de "down, down from, from, off; concerning" , also used as a prefix in Latin usually meaning "down, off, away, from among, down from," but also "down to the bottom, totally" hence "completely" (intensive or completive), which is its sense in many English words. As a Latin prefix it also had the function of undoing or reversing a verb's action, and hence it came to be used as a pure privative -- "not, do the opposite of, undo" -- which is its primary function as a living prefix in English, as in defrost(1895), defuse (1943), etc. Compare also dis-.

eg. deceleration, demulcent, detergent 

2) hydro-: before vowels hydr-, word-forming element in compounds of Greek origin, meaning "water," from Greek hydro-, comb. form of hydor "water" .

eg. hydro-electric, hydropower, hydrocortisone

2. Extra Words

1) Kleenex: proprietary name, registered by Cellucotton Products Company, Neenah, Wisconsin, U.S.; later Kimberly-Clark Corp. An arbitrary alteration of clean + brand-name suffix -ex.

2) Pad/Sanitary napkin:  an absorbent item worn by a woman while she is menstruating, while she is recovering from vaginal surgery, for lochia (post-birth bleeding), after an abortion, or in any other situation where it is necessary to absorb a flow of blood from the vagina.

3) Tampon: "plug of cotton to stanch a flow of blood (especially from the vagina)," 1848, from French tampon, from Middle French tampon "plug" . Tampax, proprietary name registered in U.S. 1932, is based on tampon.