pronoun
other, another
A1
Means 'other' or 'another' used as an indefinite adjective/pronoun to refer to a different person or thing. It is fully declinable (anderer, andere, anderes, etc.) and agrees with gender, number and case. No special preposition; watch agreement and endings in noun phrases.
Examples
Der eine Mitarbeiter kündigte, bevor der andere seine Aufgaben übernehmen konnte.
One employee resigned before the other could take over his tasks.
Er hat einen anderen Vorschlag.
He has a different suggestion.
Nimm einen anderen Stift.
Take another pen.
Details
Mnemonics
picture two identical items and one labeled 'ander' (the other one)
think 'another' ~ 'ander'
Notes
'ander-' is a stem used to form declinable forms like 'anderer', 'andere', 'anderes'.