Yod = 10, ordinal 10, reduced 1, no final form. Spelled in full, יוד = 10+6+4 = 20.
Meaning
Yod is 'hand' and the smallest character in the script, the one the Gospels make the unit of the law's permanence ('not one yod shall pass'). Its 10 is the number of the sephiroth and of the commandments, and the Kabbalists read the yod as the seed-stroke from which the other letters are formed, which is close to the truth of the script, where several letters begin as a yod extended.