앞뒤로 또는 이리저리 움직이는 상태를 나타내며, 주로 'to and fro'라는 관용구로 사용됨.
Away or back; used almost exclusively in the phrase 'to and fro' to indicate movement in opposite directions.
예문:
"The heavy pendulum continued to swing to and fro with rhythmic precision."
"He paced to and fro in the corridor while waiting for the news."
"The branches of the willow tree swayed to and fro in the gentle breeze."