Also see definition of "Celestial" in Word Study
Study Dictionary
Celestial
CELESTIAL [ISBE]
CELESTIAL - se-les'-chal (epouranios, "above the sky," "heavenly"): Peculiar to Paul's majestic argument on the resurrection: celestial verses terrestrial bodies (1 Cor 15:40) with reference possibly to sun and moon, etc., but more probably to the bodies of angels in distinction from those of beasts and mortal men (compare Christ's words, Mt 22:30; Lk 20:36); including also doubtless in the apostle's thought the resurrection-body of Jesus and of the saints already taken-into glory. Light is thrown on its meaning by the rendering of the same Greek original as "heavenly places" (Eph 1:3,20; 2:6; 3:10); "heavenly" (1 Cor 15:48). Hence, "celestial" as used by Paul indicates the soul's continued life beyond the grave, the spiritual body of the redeemed in heaven, who, in Christ, have put on immortality.Dwight M. Pratt
Also see definition of "Celestial" in Word Study