If you're looking for a word that conveys a similar meaning to "mother" in a more formal or poetic context, you might consider options like:
* Mater (Latin)
* Mère (French)
* Madre (Spanish)
* Mutter (German)
However, these words don't necessarily have the same connotations as "mother" and wouldn't be interchangeable in all contexts.
Can you give me more context about where you need this word? Knowing the situation might help me suggest a better alternative.