This is the 4111th most frequent Japanese word.
マッサージ
Massage.
In this sentence, 'マッサージ' is used as a noun referring to the act or session of massage therapy.
昨日は肩こりがひどかったので、マッサージに行きました。
Yesterday, I had severe shoulder stiffness, so I went for a massage.
Here, 'マッサージ' is used as a verb, adopting the Japanese conjugation pattern of suru-verbs.
毎晩寝る前に、自分で足をマッサージしています。
Every night before sleeping, I massage my own feet.
In this case, 'マッサージ' is used as a noun indicating the action of giving massages, with the context showing someone performing it.