"Terran" And "Interstellar"

Poul Anderson's Technic History has a Terran Empire. Robert Heinlein's Citizen Of The Galaxy has a Terran Hegemony. Sf writers have coined "Terran" as an alternative to "Terrestrial."

Sf  is "interstellar" if someone in it has traversed interstellar space. Thus:

(i) extra-solar aliens have arrived here;

(ii) an exploratory expedition has departed from the Solar System;

(iii) travel between inhabited planetary systems has become routine, like trans-Atlantic air travel now. 

Robert Heinlein's seven juvenile interstellar novels divide into one of (i), one of (ii) and five of (iii).

Poul Anderson has (i) in some short stories, (ii) in Tau Zero and (iii) in many works that are familiar to us.

In Anderson's The Enemy Stars, a slower than light interstellar spaceship carries an instantaneous teleportation transceiver so that the ship can be refueled at any time and also crews can pass between Earth and the ship. In Heinlein's Tunnel In The Sky, receiverless instantaneous interstellar teleportation is possible between planetary surfaces: no spaceships needed. Impossible!