In languages that don't have a perfect 1:1 mapping between sounds and letters in their written form there are two possibilities.
- In English "bow" and "bough" are two spellings with a single pronunciation
- In English
/baʊ/are two pronunciations with a single spelling "bow".
In English both are pretty common, and as my example shows sometimes even the "same word" can be a case of both. But in other languages one case may be much more prevalent than the other. For instance in Modern Greek there are several sounds that can be spelled in multiple ways but I'm not aware of any spellings that can be pronounced in multiple ways.
What terms are used to describe languages or writing systems where 1. occurs and where 2. occurs?