sacks / sacs / sax are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
sacks: (noun) a bag made of paper or plastic for holding customer's purchases. (noun) the quantity contained in a sack. (noun) any of various light dry strong white wine from Spain and Canary Islands (including sherry). (noun) a woman's full loose hiplength jacket. (noun) the plundering of a place by an army or mob; usually involves destruction and slaughter. (verb) plunder (a town) after capture. (verb) put in a sack.
sacs: (noun) a structure resembling a bag in an animal.
sax: (noun) a Belgian maker of musical instruments who invented the saxophone (1814-1894). (noun) a single-reed woodwind with a conical bore.
sacks: s·AE·k·s
sacs: s·AE·k·s
sax: s·AE·k·s
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)