You are right to question the meaning of this word. Just another example of the English trying to confuse foreigners with our impossible language. Here are a few definitions.
noun: an apparatus used for the distillation of liquids; consists of a vessel in which a substance is vaporized by heat and a condenser where the vapor is condensed
noun: a static photograph (especially one taken from a movie and used for advertising purposes) (Example: "He wanted some stills for a magazine ad")
noun: a plant and works where alcoholic drinks are made by distillation
noun: (poetic) tranquil silence (Example: "The still of the night")
verb: make motionless
verb: lessen the intensity of or calm (Example: "Still the fears")
verb: cause to be quiet or not talk
verb: make calm or still
adjective: free from noticeable current (Example: "A still pond")
adjective: used of pictures; of a single or static photograph not presented so as to create the illusion of motion; or representing objects not capable of motion (Example: "A still photograph")
adjective: not sparkling (Example: "A still wine")
adjective: marked by absence of sound (Example: "The night was still")
adjective: free from disturbance (Example: "Scarcely a ripple on the still water")
adjective: not in physical motion
adverb: with reference to action or condition; without change, interruption, or cessation (Example: "It's still warm outside")
adverb: without moving or making a sound (Example: "He sat still as a statue")
adverb: to a greater degree or extent; used with comparisons (Example: "An even (or still) more interesting problem")
adverb: despite anything to the contrary (usually following a concession) (Example: "Granted that it is dangerous, all the same I still want to go")