In Midsummer nights dream what are Bottom flute and snouts names puns on?

All of the 'hempen homespun' characters have names that are puns or one sort or another.

Bottom is a weaver, and a 'bottom' was a type of spindle for holding yarn to be woven.

Flute is an apprentice bellows-mender: the pipe the air comes through in a bellows is a flute.

Snug is a joiner: someone who fits timber together snugly.

Snout is a tinker, he mends pots and pans: snout is another Word for 'nozzle' as on a kettle or pouring pot.

Starveling is a tailor: tailors were proverbially thin (a long and complicated backstory to this one - which there is no space for here).

Peter Quince is a carpenter: quinces or quoins are the wooden wedges a carpenter uses to hold glued objects together while the glue sets.

Several of these names also have further punning meanings (someone who 'flutes' has a thin, reedy voice - like a woman's), but those are the puns that link each mechanical to his trade.