Numbers, Their Occult Power and Mystic Virtues, by W. Wynn Westcott, [1911], at sacred-texts.com
SOME HINDOO USES OF NUMBERS.
In ancient India, in the Sanscrit language, certain words were used as equivalent to the low numbers: for One they said Moon or Earth: for Two they used many words of things in pairs such as eye, wing, arm: for Three they used Rama, fire or guna, for they knew of 3 Ramas, 3 kinds of fire and 3 gunas or qualities: for 4 they used Veda, age or ocean: for 6 they used Seasons: for 7 they used Sage or vowel: for 12 they said Sun or Zodiac; and for 20 they used nails, meaning those of hands and feet. Edward B. Tylor.