Hi, Mary. It depends on the size and context. If we are talking about gas for barbecues, we probably use cylinder and bottle interchangeably. For little containers of gas for compact camping stoves (one that could fit in a rucksack) we would call it a canister.

I am planning a barbecue this evening, so I weighed the gas cylinder this morning to check how much gas was left.

I normally call them Gas Bottles. However I think some regions of the UK will say canister. It’s personal choice really. They’re both correct.

I think "t" sound