寸草心

寸草心

Literally means:

inch grass heart

Actually means:

children's will to repay their parents' loving kindness

In one poem of Tang Dynasty, there are two lines going as: 谁言寸草心，报得三春晖 (Who says my heart like a blade of grass, could repay the love of gentle beams of spring sun?).

春晖, spring sun, means parents'loving kindness of bringing up their children; 寸草 (a blade of tender grass); 心 means children's will to repay their parents'grace.

The two lines combined mean that children can never pay off the debt of parental grace, 寸草心 when used independently, means children repay the debt of parental grace, connoting they can never pay off such a debt.

唐诗中有这样的话：“谁言寸草心，报得三春晖”。

“春晖”（春天的阳光）比喻父母的养育之恩，“寸草心”（寸草即小草）比喻子女报答父母养育之恩的心意。

两句合起来（可以压缩为“春晖寸草”）表示父母的恩情子女是报答不完的。“寸草心”单独使用，除表示儿女报答父母恩情的心意之外，还含有报答不尽的意思。