This is the 138th most frequent Spanish word.
espera
"Espera" in English means "wait" or "waiting."
Here, 'espera' is used as a noun meaning 'wait' or 'waiting period'.
La espera en el hospital fue más larga de lo esperado.
The wait at the hospital was longer than expected.
Here, 'espera' is a command (imperative form) directed to 'you' (informal singular), meaning 'wait'.
¡Espera! Olvidaste tus llaves.
Wait! You forgot your keys.
In this sentence, 'espera' functions as a verb in the present indicative form of 'esperar', meaning 'to wait' or 'to hope'.