What does mustard mean in cooking?

mustard means: It is a spice that has a strong flavor. (in Cooking Dictionary)

What else does mustard mean?

• One of many Eurasian plants belonging to the mustard family. White mustard, Indian mustard and black mustard are all cultivated for their edible seeds. (in Merlin Dictionary)
• Condiments made with the dried seeds of some of these plants. (in Merlin Dictionary)
• From dark yellow to light brown. (in Merlin Dictionary)
• A group of harmful organic compounds, which includes mustard gas or the nitrogen mustards. (in Merlin Dictionary)