1 not visible to the eye, either characteristically or because hidden.
2 too small to be seen or noticed.
3 artfully concealed (invisible mending).
Phrases and idioms:
invisible exports (or imports etc.) items, esp. services, involving payment between countries but not constituting tangible commodities.
Derivatives:
invisibility n. invisibleness n. invisibly adv.
Etymology: ME f. OF invisible or L invisibilis (as IN-(1), VISIBLE)
Useful english dictionary. 2012.