depuis
since (a point in the past up to the present)
for (a duration continuing into the present)
J'attends le bus depuis vingt minutes.
I've been waiting for the bus for twenty minutes.
from (indicating origin or starting point, often spatial or viewpoint)
On a une super vue sur la mer depuis le balcon.
We have a great view of the sea from the balcony.
Notes
GENERAL INFO
depuis is a preposition meaning "since" (a point in time) or "for" (a duration, emphasizing an action that started in the past and continues to the present).
USAGE
Use depuis to express:
A starting point: *Je travaille ici depuis 2015.* (I've worked here since 2015.)
A duration for an ongoing action: *Elle étudie le français depuis six mois.* (She has been studying French for six months.)
TRAPS
Do not confuse depuis (ongoing action) with *pour* (future duration or purpose).
Example: *J'habite à Paris depuis deux ans.* (I've lived in Paris for two years - and still do).
Incorrect: *J'habite à Paris pour deux ans.*
