Now updated for CSW19. New words, if any, and new inflections of existing words, are shown in red.
| afresh | again |
| again agen agin | once more. |
| algate algates | always; wholly; everywhere. |
| alway always | at every time. |
| ance | once. |
| anew | afresh, again. |
| annual | happening every year > ANNUALLY; (noun) a plant that flowers for one year only. |
| biannual | taking place twice a year > BIANNUALLY; (noun) something appearing, occurring, etc., twice a year. |
| biennial | taking place every two years > BIENNIALLY; (noun) something appearing, occurring, etc., every two years. |
| biennium | a period of two years > BIENNIA or BIENNIUMS. |
| bihourly | taking place every two hours. |
| bimensal | occurring every two months. |
| bimestrial | occurring every two months; lasting for two months. |
| bimestrially | in a bimestrial fashion. |
| bimillennial | recurring every two thousand years. |
| bimonthly | a periodical that comes every other month. |
| biquarterly | happening every second quarter. |
| biweekly | a periodical that comes every other week. |
| biyearly | every two years. |
| centennial | recurring every hundred years > CENTENNIALLY; lasting a hundred years; (noun) a hundredth anniversary. |
| circadian | occurring every 24 hours. |
| dailiness dailyness | the quality of being DAILY. |
| daily | taking place every day. |
| decennial | happening every ten years > DECENNIALLY. |
| diarial diarian | pertaining to a diary; daily. |
| duodecennial | recurring twelve years. |
| everyday | taking place every day. |
| everywhen | on every occasion. |
| fortnightly | taking place once a fortnight. |
| frequent | often > FREQUENTLY. |
| frequentness | the state of being FREQUENT. |
| hebdomadal | occurring once every seven days; weekly > HEBDOMADALLY. |
| hourly | taking place every hour. |
| ilkaday ilkadays | every day, every day but Sunday. |
| infrequent | not frequent > INFREQUENTLY. |
| mensal | monthly. |
| monthly | occurring every month; (noun) a monthly periodical > MONTHLIES. |
| nightly | taking place every night. |
| novennial | recurring every ninth year. N.B. no NOVENNIALLY*. |
| octennial | recurring every eighth year > OCTENNIALLY. |
| oft | often > OFTER, OFTEST. |
| often | happening many times > OFTENER, OFTENEST. |
| oftenness | frequency. |
| oftentimes | often, repeatedly. |
| ofttimes | often. |
| once | one time. |
| onst | once. |
| periodic | happening at set intervals. |
| quarterly | occurring every quarter (three months); (noun) a periodical appearing once every three months > QUARTERLIES. |
| quinquennial | occurring every fifth year > QUINQUENNIALLY. |
| seldom | not often > SELDOMLY. |
| semestral | half-yearly. |
| semimonthly | (something) issued or happening twice a month. |
| semiweekly | (something) issued or happening twice a week. |
| semiyearly | issued or happening twice a year. |
| semper | (Lat.) always. |
| sexennial | happening once in six year > SEXENNIALLY. |
| sometimes | happening from time to time. |
| somewhiles | sometimes. |
| sporadic | at irregular intervals. |
| statedly | at stated times; regularly. |
| triennial | happening every third year, or continuing for three years > TRIENNIALLY; (noun) a period of three years > TRIENNIALS. |
| trieteric | occurring in alternate years. |
| trimonthly | every three months. |
| triweekly | occurring or appearing three times a week. |
| unoften | not often. |
| unseldom | not seldom. |
| vicennial | occurring every twenty years. N.B. no VICENNIALLY. |
| weekly | happening every week. |
| whenever | at every time when. |
| yearly | occurring every year; (noun) a publication appearing once a year. |
| yince | (Scots) once. |