妙法蓮華經玄義 6.105

6.105

伽陀者，一切四言、五言、七、九等偈，不重頌者，皆名伽陀也。

As for *gāthā*, all verses of four syllables, five syllables, seven, nine, and so forth that do not recapitulate [prose] are named *gāthā*.