Question:Can you tell me what the Bible says concerning growing into a man? I've heard that† adolescent or a child was from 0-19, and that ages 20-39 was considered a young man, and that 40 and over was adulthood. Can you help me with scriptures or even necessary inferences?
As we look into this topic, remember that views on when someone is considered "old enough" varies by culture and the Bible spans 1,500 years and numerous cultures. We also must keep in mind that in the yearly years of mankind, we lived a lot longer and that will impact how that era categorized people. But what you find is that in both the Hebrew and Greek the terms were loosely used. Precise age ranges were not used like we do.
In the womb
Harah: As a verb it means to conceived. As an adjective it means to be pregnant.
Yaladh: It means to give birth to, to bear a child.
'Olal: A newborn (I Samuel 15:3), a stillborn (Job 3:16)
Yanaq: A nursing child
Waladh: descendant, child. Only used in Genesis 11:30, II Samuel 6:23
Zakhar: Male offspring. Can be of any age (Leviticus 27:3-7).
Neqevah: Female offspring. Can be of any age (Leviticus 27:3-7).
Yeledh: A boy. Used for a child not yet born (Exodus 21:22), a newborn (Ruth 4:16; II Samuel 12:18-22), a nursing child (Genesis 21:8; Exodus 2:3), a youth in his late teens (Genesis 21:14-16; 37:30), a young man (Genesis 44:20 - Benjamin was about 23 years old at this time and the father of ten children, Genesis 46:21), childhood friends (I Kings 12:14 - Rehoboam was 41 at this time).
Yaldah: A girl. A child playing (Zechariah 8:5), old enough to marry (Geneis 34:4). Probably the same range of meaning as yeledh.
Na'ar: Young, immature, inexperienced male. Not yet born (Judges 13:5), newborn (I Samuel 4:21), infant (I Samuel 1:22), weaned (I Samuel 1:27), teenager (Genesis 37:2 - Joseph is about 17; II Chronicles 34:3 - Josiah was 16), adult (Genesis 41:12 - Joseph is 30), young warriors (I Samuel 25:9; II Samuel 18:5). Basically this word is the opposite of zaqen (old).
Na'arah: Young, immature, inexperienced female: young woman (I Samuel 9:11), a betrothed woman (Esther 2:4), a married woman (Ruth 2:6).
No'ar: The period of one's youth (Job 33:25; 36:14; Psalms 88:15; Proverbs 29:21).
Yaldhuth: A youth, childhood. (Psalms 110:3; Ecclesiastes 11:9-10).
Bachur: Unmarried male (Deuteronomy 32:25; Isaiah 62:5) but not a child (Ezek 9:6). Old enough to be in the military (Jeremiah 18:21; 51:3; Ezekiel 23:6). Old enough to be called strong (Proverbs 20:20).
Bethulawh: Unmarried female, virgin (Leviticus 21:13; Deuteronomy 22:19), but not a child (Psalm 148:12), yet of maritable age.
Bechuroth: The period of being a young adult (Ecclesiastes 11:9; 12:1)
Zaqen: The opposite of na'ar (young). No longer bearing children (Genesis 18:13), retired (I Samuel 8:1; I Chronicles 23:1), grey haired (Proverbs 23:22), experienced, mature (Psalms 37:25), body failing (Genesis 18:12; 27:1; I Kings 1:1, 15).
Younger or Youngest
Qaton, the root word of qotanim, has a range of meanings in comparing two things from small (as opposed to large when referring to things), insignificant (as opposed to important), or young (as opposed to old). The dividing line isn't under consideration between the contrasts. It isn't like anything under 19 inches is small. Qaton is used when one item is the smallest of the set. Or if you were talking about a set of children, qaton applied to the youngest of the descendents.
Brephos: infant. Still in the womb (Luke 1:41), newborn (Luke 2:12).
Paidion: infant (Luke 2:21), small child (Matthew 18:2-6; Luke 11:7), child (Luke 2:40).
Nepios: child, opposite of being an adult (I Corinthians 13:11).
Pais: infant (Matthew 2:16 - two and under), child (Luke 9:42), preteen (Luke 2:43 - Jesus was 12; Luke 8:51 - the girl was 12), young man (Acts 20:12).
Korasion: young girl up to maritable age. A twelve year old (Matthew 9:24-25; Mark 5:41-42). A full grown young woman (Matthew 14:11; Mark 6:22, 28).
Teknon: a descendent.
Neanias: used in classical Greek for people from their later teens to early forties. Young man (Acts 20:9), Paul's nephew (Acts 23:17-18).
Neaniskos: Also used broadly for no specific age. The rich young ruler (Matthew 19:20-22), the young man (Mark 14:51), the widow's son (Luke 7:14), opposite of old men (Acts 2:17), not little children or fathers (I John 2:13-14).
Aner: man, husband. Not a child (I Corinthians 13:11).
Gune: woman, wife.
Presbuteros: Older person, not a young man or woman (I Timothy 5:1-2).