on occasion

noun

1. a particular time, especially as marked by certain circumstances or occurrences: They met on three occasions.
2. a special or important time, event, ceremony, celebration, etc.: His birthday will be quite an occasion.
3. a convenient or favorable time, opportunity, or juncture: This slack period would be a good occasion to take inventory.
4. the immediate or incidental cause or reason for some action or result: What is the occasion for this uproar?
5. (in the philosophy of Alfred North Whitehead) the coincidence of the eternal objects forming a specific point-event.
6. occasions, Obsolete.
   1. needs or necessities.
   2. necessary business matters: to go about one’s lawful occasions.

verb (used with object)

7. to give occasion or cause for; bring about.

Idioms

8. on occasion, now and then; from time to time; occasionally: She visits New York on occasion.

noun

1. (sometimes foll by of) the time of a particular happening or event
2. (sometimes foll by for) a reason or cause (to do or be something); groundsthere was no occasion to complain
3. an opportunity (to do something); chance
4. a special event, time, or celebrationthe party was quite an occasion
5. on occasion every so often
6. rise to the occasion to have the courage, wit, etc, to meet the special demands of a situation
7. take occasion to avail oneself of an opportunity (to do something)

verb

8. (tr) to bring about, esp incidentally or by chance

n.late 14c., “opportunity; grounds for action, state of affairs that makes something else possible; a happening, occurrence,” from Old French ochaison, ocasion “cause, reason, excuse, pretext; opportunity” (13c.) or directly from Latin occasionem (nominative occasio) “opportunity, appropriate time,” in Late Latin “cause,” from occasum, occasus, past participle of occidere “fall down, go down,” from ob “down, away” (see ob-) + cadere “to fall” (see case (n.1)). The notion is of a “falling together,” or juncture, of circumstances. v.mid-15c., “to bring (something) about,” from occasion (n.), or else from Old French occasionner “to cause,” from Medieval Latin occasionare, from Latin occasionem (see occasion (n.)). Related: Occasioned; occasioning. From time to time, now and then, as in Nell has been known to eat meat on occasion. This usage, first in the form of upon occasion, replaced by occasion about 1600. see on occasion; rise to the occasion.