A telescope is an instrument designed for the observation of remote objects by the collection of electromagnetic radiation. The first known practically functioning telescopes were invented in the Netherlands at the beginning of the 17th century. "Telescopes" can refer to a whole range of instruments operating in most regions of the electromagnetic spectrum.

The word "telescope" (from the Greek t??e, tele "far" and s??pe??, skopein "to look or see"; t??es??p??, teleskopos "far-seeing") was coined in 1611 by the Greek mathematician Giovanni Demisiani for one of Galileo Galilei's instruments presented at a banquet at the Accademia dei Lincei.
In the Starry Messenger Galileo had used the term "perspicillum".