Decoding exercises: "orV" and "orrV"

The letter O in the sequences "orV" and "orrV" where V is any vowel, normally sounds /ɒ/ in Received Pronunciation (as in orange) but in some cases it sounds /ɔː/ (as in story) or /ə/ when unstressed (as in category). It also can be silent as in history.

In General American /ɒr/ sounds /ɑːr/ in only 5 words and it sounds /ɔːr/ in the rest.

In regional Atlantic American English /ɒr/ sounds /ɑːr/, as in orange pronounced /ˈɑːrɪndʒ/.

Common words

 * As /ɒ/, /ɔː/: correspond - foreign - forest - historical - majority - moral - orange - origin - priority
 * As /ɒ/, /ɑː/: borrow - sorry - tomorrow
 * As /ɔː/: boring - explorer - moreover - story
 * As /ə/: contemporary /kənˈtemprəriː, kənˈtempərəriː/ - corporate - corporation - correct - exploration - factory - /ˈfæktəriː, fæktriː/ - history /ˈhɪstəriː, ˈhɪstriː/ - ignorant - memory - original - temporary /ˈtempərəriː, ˈtemprəriː/- terrorist - theory - victory
 * As /ʌ/ or /ɜː/: thorough /ˈθʌrə, ˈθɜːroʊ/ - worry /ˈwʌriː, ˈwɜːriː/

Less common words

 * As /ɒ/, /ɔː/: categorical - coral - historic - horrible - horror - laboratory /ləˈbɒrətriː, ˈlæbrətɔːriː/ - minority - seniority
 * As /ɒ/, /ɑː/: morrow (shortening of "tomorrow") - sorrow
 * As /ɔː/: chlorine - choral - glory - historian - laboratory /ləˈbɒrətriː, ˈlæbrətɔːri/ - memorial - notorious - storage
 * As /ə/ or /ɔː/: category - mandatory - territory /ˈterɪtəriː, ˈterɪtriː, ˈterətɔːriː/
 * As /ə/: compulsory - forever - herbivorous

Proper nouns

 * As /ɒ/, /ɔː/: Boris, Dorothy, Florence, Forida, Oregon
 * As /ɔː/: Dora
 * As /ə/: Colorado, Deborah /ˈdebərə, ˈdebrə/, Korea, Morocco

Spelling rule
The sequence "orr" is pronounced /ɔː/ in Received Pronunciation only in verbs ending in "or". There is only one such a verb that appears in normal dictionaries:
 * from abhor: abhorred, abhorring

Note that "abhorrent" /əbˈhɒrənt/ is an adjective, not a verb.