the act of communicating with a deity (especially as a petition or in adoration or contrition or thanksgiving)
"the priest sank to his knees in prayer"
a fixed text used in praying
"The priest read from the ancient prayer before beginning the ceremony."
someone who prays to God
"The priest welcomed every attendee as a prayer before leading the service."
A practice of communicating with one's God.
"The prayer knelt quietly by the window, waiting for his sister to join him in silence."
One who prays.
In plain English: Prayer is when you talk to God or a higher power, either asking for help or just sharing your thoughts.
"She started her day with a quiet prayer for her family's safety."
Usage: Prayer is an expression of hope or request to a deity, not the person making that request. If you need a word for someone who prays, use worshiper or petitioner instead.
The word prayer entered English from the Old French preiere and earlier Latin roots related to making requests. It eventually replaced the native Old English word ġebed, which is the ancestor of the modern term "bead."