third class, 3rd, 3rd calendar sign
丙 centers on the idea of ranking third in a sequence: the third class, third item, or the third calendar sign. It is a label for ordinal position rather than a quality description.
丙 is an ancient pictograph whose original meaning is uncertain. It was later borrowed to represent the third of the ten celestial stems, used for ordinal numbering and calendar signs.
The top stroke 一 and the inner 人-like shape inside 冂 can be seen as a label: one over a person in a box, marking it as the third item in a set.
For ヘイ, imagine a third-place athlete saying 'Hey!' in frustration: 'Hey!' -> ヘイ, because they came in third.
third rank; third class; third person (in a contract, etc.)
Fire Horse (43rd term of the sexagenary cycle, e.g. 1906, 1966, 2026)
third division of the night (approx. 11pm to 1am)
Fire Rat (13th term of the sexagenary cycle, e.g. 1936, 1996, 2056)
Fire Tiger (3rd term of the sexagenary cycle, e.g. 1926, 1986, 2046)
Fire Dog (23rd term of the sexagenary cycle, e.g. 1946, 2006, 2066)
Fire Monkey (33rd term of the sexagenary cycle, e.g. 1956, 2016, 2076)
third grade; third class; C-grade
Fire Dragon (53rd term of the sexagenary cycle, e.g. 1916, 1976, 2036)
A, B and C; first, second and third
A, B, C and D; first, second, third and fourth