Collins Chinese Dictionary Plus (3rd edition), 2011:
同行 tóngháng 动
be in the same line of work
- 他的父母是同行,都是老师(師)。 Tā de fùmǔ shì tóngháng,dōu shì lǎoshī. His parents are in the same line of work they are both teachers.
同行 tóngxíng 动
travel together