preposition
from (a time), starting (from)
A1
ab: preposition meaning 'from' (a time) or 'starting from'. Used for dates, times and points of departure. It governs the dative (e.g., ab dem 1. Juli). Not reflexive; no auxiliary. Common in temporal phrases to indicate when something begins or takes effect.
Examples
Ab heute darfst du den Schlüssel benutzen.
From today you may use the key.
Ab dem nächsten Monat zahlten die Kunden, die das Abo nicht verlängerten, eine höhere Gebühr.
Starting next month, customers who did not renew the subscription paid a higher fee.
Der neue Fahrplan gilt ab dem 1. Mai.
The new timetable is valid starting from May 1st.
Details
Mnemonics
Picture a clock hand moving away from a point — 'ab' meaning 'from that time'
sounds like English 'off' (both indicate separation)
n/a
Notes
'Ab' as a preposition commonly takes the dative when used with dates or times (e.g., 'ab dem 5. Juni'). It can also function as a prefix in separable verbs (abfahren, abholen).