This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. Data that describes other data, serving as an informative label.

n. data about data

"The term metadata breaks down into an an interesting definition."

information    data   

tag   

metainformation   

schema    template    onechar    markup    contention    design-time