container vs mailer

Other hyponyms of container include bag, bag, handbag, pocketbook, purse, basket, handbasket, bin, bowl, pipe bowl, box, bread-bin, breadbox, bunker, can, tin, tin can, canister, cannister, tin, capsule, cargo container, case, case, display case, showcase, vitrine, cassette, cup, cylinder, dice box, dice cup, dish, dispenser, drawer, Dumpster, empty, envelope, drinking glass, glass, grab bag, magnetic bottle, manger, trough, measure, cast, mold, mould, package, parcel, pan, fuel pod, pod, flowerpot, pot, powder flask, powder horn, receptacle, reliquary, saltcellar, bank, coin bank, money box, savings bank, coal scuttle, scuttle, shaker, spoon, storage ring, thimble, time capsule, vessel, circular file, waste-paper basket, waste basket, wastebasket, wastepaper basket, watering can, watering pot, workbag, workbasket, workbox.