number of people
Refers to a count of people, similar to にんずう but with a slightly more formal or literary feel. Often used in contexts like headcounts or attendance.
See also: 人数 (にんずう)
Please check the number of people for the meeting.
being counted as an adult
Rare usage referring to someone being considered a full-fledged adult, often in the context of counting people for a purpose. More commonly expressed as 一人前 or 大人として数えられる.
In the old days, you were counted as an adult at fifteen.
人数が足りないので、もう一人呼びましょう。
We don't have enough people, so let's call one more.
Compound of 人 (ひと, 'person') and 数 (かず, 'number'). The reading ひとかず is the native Japanese reading (kun'yomi) of the kanji, while にんずう uses the Sino-Japanese readings.