expression, godan verb (-su)
lend one's shoulder; support with one's shoulder; help carry a load
Literally offering one's shoulder for physical support, such as helping an injured person walk or sharing a heavy load.
足をくじいた友達に肩を貸して家まで送った。
I lent my shoulder to a friend who sprained his ankle and walked him home.
重い荷物を
I helped carry the heavy luggage by lending a shoulder.
expression, godan verb (-su)
lend a hand; come to someone's aid
Figurative extension: offering help or support in a difficult situation, not necessarily physical.
仕事が忙しいときは、いつも同僚が肩を貸してくれる。
When work gets busy, my colleague always lends a hand.
困っているなら、私が肩を貸しましょう。
If you're in trouble, I'll come to your aid.