Archaic name for the first month of the lunar calendar, equivalent to 睦月 (むつき). Used in historical or traditional contexts.
See also: 睦月
In the old lunar calendar, 太郎月, like 睦月, refers to the first month.
The exact derivation is uncertain; the spelling 太郎月 is conventionally associated with the first lunar month, possibly from the idea of the 'eldest son' (太郎) as the first month.