i.e.
abbreviation
- that is to say (used to add explanatory information or to state something in different words)换而言之（用以补充说明, 同that is to say） ：
a walking boot which is synthetic, i.e. not leather or suede.
人造革皮靴, 也就是说, 不是皮革的, 也不是绒面革的。
词源
from Latin id est 'that is'.