息

息

Breath; breathing.

Here, '息' (iki) is used to mean 'breath' in the context of respiration.

私は深く息を吸いました。

I took a deep breath.

'息づかい' combines '息' (breath) with 'づかい' (usage) to refer to someone's way of breathing.

彼の息づかいが速くなってきました。

His breathing became faster.

Here, '息' is associated with the act of breathing, and '息が詰まる' is a phrase expressing feeling suffocated or stifled.

この部屋に入ると息が詰まる気がする。

It feels suffocating when entering this room.