1. 折纸 (zhé zhǐ)
* 折 (zhé): to fold
* 纸 (zhǐ): paper
This is the most common and direct translation of origami.
2. 叠纸 (dié zhǐ)
* 叠 (dié): to fold (can also mean "to pile up")
* 纸 (zhǐ): paper
This is a less common translation, but still valid.
Both translations are pronounced "zhé zhǐ" or "dié zhǐ" in Mandarin Chinese.