alto! or para!

Question

When I watch a spanish movie and someone is told to "stop!", it seems they always say "alto!". When I look up "to stop" in this dictionary it only says parar, which would be "para!" in the 3rd person singular. If you look up alto in the dictionary it does say it's an exclamatory for stop.

I'm wondering if both work for "stop!" or is one more acceptable than the other.

Answer 1

"Alto" when used this way is an interjection as a command meaning to stop doing something, but it is a noun. When talking about height, it is an adjective.

"To stop" is "parar" and "pararse."

"Alto" as a noun is only used as a verbal command and on stop signs.

Answer 2

The police say "¡Alto¡" when chasing someone and so do the traffic signs.

To ask someone, such as the bus driver, to stop you'd "Pare aquí, por favor."