once a
fixed phr..fixed phr.. A phrase used to say how often something happens. You complete it with a period of time, like 'once a week' or 'once a month', to mean one time during that period.
fixed phr.. A fixed expression used to state the frequency of an event, meaning one occurrence per specified unit of time. The structure is `once + a/an + [singular time noun]`.
I go to the gym once a week.
The book club meets once a month to discuss a new novel they have all read.
The committee is required to convene at least once a year to review its charter and report on its activities to the main board.
This phrase is followed by a singular noun for a period of time, such as 'day', 'week', 'month', or 'year'.
Contrast 'once a...' with 'twice a...' and 'three times a...'; highlight that 'once' and 'twice' are special words for frequency, whereas higher numbers use the '... times' pattern.
I go to the gym one time a week.I go to the gym once a week.For the number one, use the special word 'once' to talk about frequency, not 'one time'.