heading vs excavation

heading and excavation both are nouns.

Word	Noun	Adjective	Verb	Adverb
heading	Yes	No	No	No
excavation	Yes	No	No	No

heading (noun)	excavation (noun)
a horizontal (or nearly horizontal) passageway in a mine	the act of extracting ores or coal etc from the earth
a line of text serving to indicate what the passage below it is about	the act of digging
the direction or path along which something moves or along which it lies	a hole in the ground made by excavating
	the site of an archeological exploration