Example sentences
zhè这ge个cí词shì是shén什me么yì意si思？
What does this word mean?
wǒ我míng明bái白nǐ你de的yì意si思。
I understand what you mean.
About this word
意 is intent, the noise your heart makes, and 思 is thinking. Together they name what a word or a person is getting at, meaning as the thing you were aiming at when you spoke. 意思 punches far above its size: 什么意思 is what do you mean, 有意思 is interesting, 没意思 is boring, 不好意思 is sorry or embarrassing, 小意思 is a trifle. Five everyday phrases from one word, which is a good return on two characters.
The story behind the character
意
意 is 音 (sound) sitting on 心 (heart). Sound stacked on feeling: what you mean is the noise your heart makes. Xu Shen wrote 意，志也, the intent, what you're aiming at inside. So 意思, the everyday word for meaning, has a sound on top and a heart underneath. Somebody asking 什么意思 wants to know what your heart is saying.
思
思 looks like 田 (field) over 心 (heart), which is a lovely picture and the wrong one. The top was originally 囟, the soft spot on a baby's skull, standing in for the head. So it's head above heart, and that's thinking: skull and heart going at it together. By the modern script 囟 had flattened into 田, and the field moved in.