The proper term for the sexual organs, that produce the sperm, located outside of the body, in the 'sac'. The two egg shaped spheres.
Testicle is the singular term, referring to just one of the male sex organs more commonly called 'the balls', while 'testes' is the plural, the proper term to use when describing both of the male sex organs, that produces the sperm.
Testicle(s) or Testes are the factory that produces the sperm and testosterone (among other androgens) which are located within the scrotum.
Taken from the Latin word 'testiculus' which is the diminutive of the Latin testis, which means 'witness of'
In Ancient Rome, a single witness to a transgression was not accepted, they required two witnesses, and these were referred to as the Testis, as they always came in pairs.
In swearing to tell the truth, the witnesses placed a hand over their scrotum, (similar to today's swearing in, where one places a hand on the Bible.) which later evolved to where it became associated with the sexual reproduction organs, now referred to as the 'testes'.
"In witness of one's virility or manhood".
These are the reproductive system, comprising of the gonads, and the endocrine system.
The Gonads (a common name used to describe the testes) produce the sperm.
The endocrine system produces the hormones, with testosterone being the most well known one, though there are others produced.
For most males, there are two testicles, contained on the exterior of the male groin, within the scrotum, which is usually also covered in pubic hairs.
The scrotum is an extension of the abdomen.
The 'testes' contain very fine coiled tubes, which are lined with a layer of cells.
These cells produce the sperm, from puberty to old age.
Between these tubes, are special cells that produce the testosterone and other androgens (hormones).
Practice (Associated Acts):
The cremasteric muscle, part of the spermatic cord, causes the testes to rise or fall, in order to maintain optimum sperm production temperature.
Upon contraction, the testes are raised, for additional body warming, and when needing to cool, the muscle relaxes.
This is called the cremasteric reflex, and many associate with an impending ejaculation.
It is noted, that upon actual orgasm, this muscle relaxes.
One can also make this action occur at will, by the flexing of one's stomach or abdomen muscles.
In most mammals, it is common for one of the testes to hang lower than the other, with about 65% of men, reporting that for them, it is the left testicle that hangs lower than the right.
This is accounted for, by the differences in vascular anatomical make up between the right and left sides of the body.
The testes work best, at a temperature just slightly less than normal body temperature, which explains their development outside of the body, as an appendage.
Production of sperm, is generally found to be more in those who have multiple sex partners.
The volume also seems to be greater in those who have multiple partners, within the animal kingdom.
The largest testicle, belonging to a whale, weighs in, on the average, of about 500 kg. which is about 1100 pounds.