What's the difference between young and youthhood?

Young

Definition:

(superl.) Not long born; still in the first part of life; not yet arrived at adolescence, maturity, or age; not old; juvenile; -- said of animals; as, a young child; a young man; a young fawn.
(superl.) Being in the first part, pr period, of growth; as, a young plant; a young tree.
(superl.) Having little experience; inexperienced; unpracticed; ignorant; weak.
(n.) The offspring of animals, either a single animal or offspring collectively.

Example Sentences:

(1) However, four of ten young adult outer arm (relatively sun-exposed) and one of ten young adult inner arm (relatively sun-protected) fibroblasts lines increased their saturation density in response to retinoic acid.
(2) The availability and success of changes in reproductive technology should lead to a reappraisal of the indications for hysterectomy, especially in young women.
(3) The very young history of clinical Psychology is demonstrating the value of clinical Psychologist in the socialistic healthy work and the international important positions of special education to psychological specialist of medicine.
(4) On the other hand, the majority of gynecologic patients with pelvic infections are young and healthy.
(5) The authors followed up the occurrence of inflammation-mediated osteopenia (IMO) in young and adult rats weighing 50 g and 150 g, respectively.
(6) Blocks of hippocampal tissue containing the fascia dentata were taken from late embryonic and newborn rats and transplanted to the hippocampal region of other newborn and young adult rats.
(7) Hanley Ramirez was hitting behind Michael Young and now he's injured.
(8) Furthermore, the analyses indicated an important interplay between environmental sources and social factors in the determination of hand lead and blood lead levels in very young children.
(9) A tall young Border Police officer stopped me, his rifle cradled in his arms.
(10) Rifampin is recommended as a prophylactic treatment for intimate contacts of young children who develop invasive infections with Haemophilus influenzae type B (Hib).
(11) The young European idealist who helped Leon Brittan, the British EU commissioner, to negotiate Chinese entry to the World Trade Organisation, also found his Spanish lawyer wife in Brussels.
(12) Younge, a former head of US cable network the Travel Channel, succeeded Peter Salmon in the role last year.
(13) A young man being treated with primary adjuvant Adriamycin and DDP for osteogenic sarcoma is described who developed a gingival line which temporally was related to DDP administration.
(14) N-Acetyl-beta-D-glucosaminidase (GAD) activities did not change significantly duringlate fetal, neonatal or young adult stages but increased significantly with advancing age.
(15) The mean value of peak Vcf showed no significant difference among young and elderly groups except for the group in the 30's which showed significant (p less than 0.05) difference between other groups.
(16) Eaton-Lambert or myasthenic syndrome was diagnosed in a young woman with recurrent small-cell carcinoma of the cervix.
(17) This analysis is based on a ranking of neighbourhoods according to the participation of young people in higher education.
(18) • young clownfish will lose their ability to "smell" the anemone species that they shelter in.
(19) Two young patients presented with generalised lymphadenopathy, otorrhoea, otitis, and rash.
(20) The effect of dietary fluoride (F) on nephrocalcinosis was studied in young, female rats.