trace [family]
"Trace amount": very small amount (chemistry). "Without a trace" = disappear completely. "Trace element": essential nutrient in tiny amounts.
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a small or barely detectable sign of something
There was no trace of blood on the knife.
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to follow or find the source or course of something
They traced the call to a number in Paris.
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to draw or copy by following lines through thin paper
She traced the picture onto her notebook.
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to go back over (the same route that one has just taken)
He began to retrace his steps.












