An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Any → occurrence of a → variable  x in an x-bound part of a → wff.

→ bound; → occurrence.

An → occurrence of a → variable in a → wff, → iff it is not a → bound occurrence.

→ bound; → occurrence.

1) The action, fact, or instance of occurring.
2) Something that happens; event; incident (Dictionary.com). 3) Logic: → bound occurrence; → free occurrence.

Verbal noun of → occur.