occur */*/*/

UK [əˈkɜː(r)] / US [əˈkɜr] verb [intransitive]
Word forms "occur":
present tense I/you/we/they occur he/she/it occurs present participle occurring past tense occurred past participle occurred

Get it right: occur:

Don't write the -ed and -ing forms of occur with only one "r". The correct spellings are occurred and occurring:
Wrong: It never ocured to me that I could be wrong.
Right: It never occurred to me that I could be wrong.
Wrong: Many changes are occuring at every level of education.
Right: Many changes are occurring at every level of education. The reason why the "r" is doubled in the -ed and -ing forms is that the stress falls on the final syllable of the verb in its infinitive form: occur. The same rule applies to most other verbs ending in -ur and -er where the stress falls on the final syllable: prefer → preferred → preferring confer → conferred → conferring concur → concurred → concurring When the stress does not fall on the final syllable, the -ed and -ing forms are spelled with one "r":
utter → uttered → uttering
cater → catered → catering
murmur → murmured → murmuring

1) to happen, especially unexpectedly

The police said that the accident occurred at about 4.30 pm.

occur in:

Complications occurred in only 5% of patients.

2) formal to exist or be found somewhere

occur in/on etc:

This small tree also occurs in central and southern India.

These are just some of the elements that occur on our planet.

Phrasal verbs:

- occur to