Origin

The character combines two components. The bottom part, 貝 (shell or precious thing), points to the meaning — shells were historically valuable and used as currency, so this radical suggests something precious or an exchange of valuables. The top part, 工, serves as a sound hint that tells you roughly how to pronounce the character, rather than adding to the meaning. Together they create a character for tribute or goods offered as payment or support, naturally arising from the image of giving precious things.