Lexical Definition

‎στάδιον‎ stádion (stad'-ee-on) stadium ^G:N-M/N
from the base of ‎ἵστημι‎ (as fixed)

furlong, race.

• a stade or certain measure of distance
• by implication, a stadium or race-course

Abbott-Smith

στάδιον, -ου, τό pl., στάδια (Jo 6:19, T), and metapl., στάδιοι (v. B1., § 9, 1), [in LXX: Da LXX 4:9*, Su 37, II Mac 11:5 12:9 ff. * ;]
a stadium, i.e.
1. a measure of length = 600 Greek feet or 1⁄8 of a Roman mile Mt 14:24 (Rec., WH, txt., R, mg.), Lk 24:13, Jo 6:19 11:18, Re 14:20 21:16, and, this being the length of the Olympic course,
2. a race-course: I Co 9:24.†

Abbott-Smith References

Liddell-Scott-Jones

στάδιος [ᾰ], α, ον,

(ἵστημι) standing fast and firm, σ. ὑσμίνη close fight, fought hand to hand, [Refs 8th c.BC+]; ἐνὶ σταδίῃ (i.e. ὑσμίνῃ) [Refs 8th c.BC+], compare σταδαῖο; [πῖδαξ] σταδίη μένει, of a spring from which no water flows, [Refs 3rd c.AD+]

__2 firm, fixed, θάλαμοι [Refs 5th c.BC+]. immobility, [Refs 2nd c.AD+]
__3 standing upright or straight, σ. χιτών,= ὀρθοστάδιον, an ungirt tunic hanging in straight plaits, [Refs 3rd c.BC+], compare στατό; θώραξ σ. a stiff breastplate, plate-armour, opposed to στρεπτός or ἁλυσιδωτός, [Refs 3rd c.BC+]
__II (ἵστημι A.IV) weighed, [Refs 2nd c.BC+]