A visit to a religious site (shrine, temple, grave) to pray or make offerings; used as a noun and commonly heard as 'o-mairi' for politeness.
明日はお寺にお参りに行く予定だ。
I'm planning to go to the temple to pay my respects tomorrow.
年末は毎年、墓参りをして祖先に祈りを捧げる。
At the end of the year I visit the grave every year to offer prayers to my ancestors.
試験の合格を祈って神社に参り、絵馬を書いた。
I went to the shrine to pray for passing the exam and wrote an ema (votive tablet).