The phrase "reckoned by the term of a year" refers to something that is measured or calculated over the course of one year. There are several synonyms that can be used to convey this concept, including "yearly," "annual," "per annum," and "once a year." "Yearly" and "annual" are perhaps the most commonly used, while "per annum" is often used in formal or technical writing. "Once a year" is a more casual alternative that can be used in everyday conversation. Regardless of the synonym used, the underlying meaning remains the same: something is being measured or calculated over a period of one year.