Meaning of dìng:
定
to fix; to set; to make definite; to subscribe to (a newspaper etc); to book (tickets etc); to order (goods etc); to congeal; to coagulate
Wǒmen xiàwǔ sān diǎn dìng le huìyì.
我们下午三点定了会议。
We set the meeting for 3 PM.
Wǒ yǐjīng bǎ zhè běn zázhì dìng le yī zhěng nián.
我已经把这本杂志定了一整年。
I have subscribed to this magazine for a whole year.
Xuèyè zài hánlěng de tiānqì zhōng kāishǐ dìng zhù le.
血液在寒冷的天气中开始定住了。
The blood began to congeal in the cold weather.
(literary) definitely
Tā jīntiān yīdìng huì zhǔnshí dào.
他今天一定会准时到。
He will definitely be on time today.