The time one has lived, usually counted by years, months, and days. The Hebrew idiom to describe the physical age of an individual was to say one was the “son of” so many years. Thus, Joseph is literally said to have died a “son of one hundred and ten years,” that is, “at the age of a hundred and ten years.” (Ge 50:26) Age may also refer to maturity. The Hebrew word sehv or seh·vahʹ (age; old age) comes from a root meaning “grow gray” and is also rendered “gray-headedness.” (1Sa 12:2; Pr 20:29) A number of Hebrew words relating to old age and aging are derived from the noun za·qanʹ, meaning “beard.” (Le 19:27) The Greek word he·li·kiʹa primarily denotes the “life span” or “age” of an individual but can also refer to one’s “physical growth” or “size.” (Mt 6:27; Joh 9:21; Lu 2:52; 19:3) Also occurring in the Greek Scriptures are geʹras (“old age”; Lu 1:36), pre·sbyʹtes (“aged man”; Phm 9), and pre·sbyʹtis (‘aged woman’; Tit 2:3). The latter two words are related to pre·sbyʹte·ros, meaning “older man; elder.”​—See OLDER MAN.

Under the Law, at the age of 20 years the men qualified for military service. (Nu 1:3) The man blind from his birth to whom Jesus gave sight must have been at least 20 years old, since his parents told their interrogators: “Ask him. He is of age. He must speak for himself.” (Joh 9:21, 23) Sarah is spoken of as being “past the age limit” for the bearing of children, as she was then some 90 years of age.​—Heb 11:11.

An age limit was set for qualification to temple service, as was an age limit at which obligatory service ceased. Some have alleged a discrepancy in the statements at Numbers 4:3, 30, 31 and 8:24-26, since the age for beginning Levitical service is stated first as from 30 years of age and  thereafter as from 25 years. However, the case seems to be that of two categories of service involved. Thus, certain rabbinic sources present the view that at the age of 25 a Levite was introduced into the tabernacle service but only to perform lighter tasks, and then, on reaching the full age of 30, he entered into the heavier tasks. They point out that the references to “the work” and “laborious service and the service of carrying loads” mentioned in Numbers 4:3, 47 do not appear at Numbers 8:24, where the age limit is 25. Others add the suggestion that those serving from the age of 30 years up had to do with the transporting of the tabernacle and its equipment when on the move, while those serving between the ages of 25 and 30 served only when the tabernacle was erected and standing at an encampment site. Those favoring the view that assignments to heavier tasks were given only at the age of 30 advance the reason that at that age greater strength, intellectual maturity, and soundness of judgment would have been attained. The Greek Septuagint gives the age as 25 at both Numbers 4:3 and 8:24. Later, in David’s day, the age limit was dropped to 20 years for beginning tabernacle service, which was in time replaced by temple service.​—1Ch 23:24-32; compare also Ezr 3:8.

As to retirement from obligatory service, this took place when the Levites reached the age of 50. The statement at Numbers 8:25, 26 indicates that at this age the Levites could still voluntarily assist those still eligible for assigned duties, but they themselves were given no direct assignment nor were they held accountable to fill such. The suggestion is made that the reason for the retirement limit for Levitical service was not merely out of consideration for their age but to prevent overcrowding of such offices. This age limit for Levites did not apply to the Aaronic high priest, for the high priest himself served in his holy office until death if he continued capable. (Nu 35:25) Aaron, Israel’s first high priest, was chosen for service when he was more than 80 and served for almost 40 years.​—Ex 7:7; Nu 33:39.

The Greek “Aion.” “Age” may also refer to a period of time in man’s history, whether having or not having datable bounds. It is frequently used to translate the Greek word ai·onʹ (plural, ai·oʹnes) in some translations. Greek lexicographers show the word to mean “space of time clearly defined and marked out, epoch, age,” and also “lifetime, life,” or “age, generation.” Since an epoch, or age, can begin and end or it can go on forever, it follows that ai·onʹ could refer to a period of time that is endless, though having a beginning. Thus, as recorded at Mark 3:29, Jesus said that the blasphemer against the holy spirit was guilty of “everlasting [agelong, perpetual, eternal] sin,” or a sin never to be canceled out at any future time. A similar expression was used with regard to the fruitless fig tree, where “forever” in the Greek is literally “to [for] the age.” (Mt 21:19) Concerning Jesus, the angelic promise was that “he will rule as king over the house of Jacob forever [literally, into the ages].”​—Lu 1:33; see TIME INDEFINITE.

However, ai·onʹ can also refer more particularly to the consistent state of things or the current state of affairs or features that distinguish a certain period of time, epoch, or age rather than to the matter of time itself. As R. C. Trench states in Synonyms of the New Testament (London, 1961, p. 203): “Thus signifying time, it comes presently to signify all which exists in the world under conditions of time; . . . and then, more ethically, the course and current of this world’s affairs.”​—See SYSTEMS OF THINGS; WORLD.