This is the 717th most frequent Japanese word.
マスク
"Mask" (e.g., face mask).
Here, 'マスク' refers to a physical face mask used for health or environmental protection.
彼は外出するときいつもマスクをつけています。
He always wears a mask when going out.
Here, 'マスク' refers to a decorative or theatrical mask, used as art or costume.
その仮面はとても奇妙にデザインされたマスクだった。
That mask had a very peculiar design.
In this example, 'マスク' is used in a technical context, meaning a masking tool in image editing.