IPA: /ˈtwɪər/
KK: /twiər/
A twier is an alternative spelling of a tuyere, which is a pipe or nozzle through which air is blown into a furnace or fire to help it burn hotter.
The blacksmith adjusted the twier to increase the airflow in the forge.
The word 'twier' originates from Old English 'twier', meaning a twist or a turn. It refers to something that is twisted or turned.
Think of something that is 'twisted' or 'turned' — that's what 'twier' means.