Cao3 in Chinese / Japanese...

草 means grass or straw in Chinese, Japanese Kanji, and old Korean Hanja.

Depending on the context, this can also mean a manuscript, draft (of a document), or rough copy. In the botany context, it can also refer to weeds, herbs, thatch, or plants.

草 is also the first character of caoshu or sōsho, the Chinese and Japanese wild cursive script style of calligraphy.

Sometimes written in variant form 艸.

This can be the surname Sou/Sō, or the given name Kusa in Japanese (there are also other romanizations for this Kanji).

This is the Chinese, Japanese Kanji, and old Korean Hanja for grassland, prairie, grass-covered plain, grasslands, meadows, Savannah, or steppe.

Sometimes also pronounced Soubaru in Japanese when used as a surname.

草莓 is the Chinese word for strawberry.

Sometimes jokingly means “love bite” (in Taiwan more than the mainland).

稻草人 is the Chinese title for a scarecrow.

The literal meaning of these characters is “rice straw person.”

誰言寸草心報得三春暉 is the last line of a famous poem. It is perceived as a tribute or ode to your parents or mother from a child or children that have left home.

The poem was written by Meng Jiao during the Tang Dynasty (about 1200 years ago). The Chinese title is “You Zi Yin” which means “The Traveler's Recite.”

The last line as shown here speaks of the generous and warm spring sunlight which gives the grass far beyond what the little grass can could ever give back (except perhaps by showing its lovely green leaves and flourishing). The metaphor is that the sun is your mother or parents, and you are the grass. Your parents raise you and give you all the love and care you need to prepare you for the world. A debt that you can never repay, nor is repayment expected.

The first part of the poem (not written in the characters to the left) suggests that the thread in a loving mother's hands is the shirt of her traveling offspring. Vigorously sewing while wishing them to come back sooner than they left.
...This part is really hard to translate into English that makes any sense but maybe you get the idea. We are talking about a poem that is so old that many Chinese people would have trouble reading it (as if it was the King James Version of Chinese).