noun
A somewhat formal or written term for a person who visits a place, such as a home, office, or event. In casual speech, お客さん or 来客 are more common.
本日の来客者は10名です。
We have 10 visitors today.
来客者用の駐車場はこちらです。
The parking lot for visitors is this way.
お客さん is the standard polite and casual term for a guest or customer. 来客者 is more formal and impersonal.
Compound of 来 (rai, 'come'), 客 (kyaku, 'guest'), and 者 (sha, 'person'). The exact historical derivation is uncertain, but the components clearly indicate 'person who comes as a guest'.