保長

(math.) distance-preserving / isometric

head of a bao 保[bao3] in the baojia 保甲[bao3 jia3] system

Bulgaria / Bulgarian / abbr. for 保加利亞|保加利亚[Bao3 jia1 li4 ya4]

to defend; to protect; to keep / to guarantee; to ensure / civil administration unit in the baojia 保甲[bao3 jia3] system (old)

length / long / forever / always / constantly

chief / head / elder / to grow / to develop / to increase / to enhance

(math.) distance-preserving correspondence / isometry