Answer:
'La vela' can mean many things. 'Vela' is a word centered in the "night watch." To stand guard at night is to 'velar.' The watch itself can also be called 'la vela.' In order to see at night, you need to light a candle, also 'la vela.' Because 'la vela' is the guard that is stood at night, its name is extended to "the night shift" generally, which can also be 'la vela.' 'La vela': Its meaning depends on how it is used in a sentence.