(purchase) order
订 (dìng) · 4 strokes
Phonosemantic compound. 讠 represents the meaning and 丁 represents the sound. Simplified form of 訂.
单 (Shàn) · 8 strokes
Simplified form of 單. Pictograph of a hunting tool or weapon constructed from rocks tied to a tree branch. The current meaning is a phonetic loan.