関手 is read as かんしゅ (kanshu) and means functor.
かんしゅ
kanshu
じこかんしゅ
endofunctor
ぜいかんてつづき
customs procedures (at the airport, etc.)
かんさい
Kansai
かんれん
relation
かんしん
concern
かんけい
influence
かかわる
to stick to (opinions)
かんしんじ
matter of concern
かんする
to concern
せき
barrier
かんけいしゃ
person concerned
かんよ
participation