張口

to open one's mouth (to eat, speak etc) / to gape / to start talking (esp. to make a request)

surname Zhang

to open up / to spread / sheet of paper / classifier for flat objects, sheet / classifier for votes

mouth / classifier for things with mouths (people, domestic animals, cannons, wells etc) / classifier for bites or mouthfuls

agape and tongue-tied (idiom); at a loss for words / gaping and speechless