Usage: 3 forms in 12 verses
Form Translated As     In Verse(s)
στηθύνιον breast LXX.Exod.29.26LXX.Exod.29.27LXX.Lev.7.31LXX.Lev.7.34LXX.Lev.8.29LXX.Lev.9.21LXX.Lev.10.14LXX.Lev.10.15LXX.Num.18.18
στηθύνια breasts LXX.Lev.9.20
στηθυνίου breast LXX.Lev.7.30LXX.Num.6.20

Liddell-Scott-Jones

στηθύνιον (stēthunion) a breast G:N-N

στηθύνιον [], τό,

diminutive of στῆθος, [LXX+4th c.BC+].

LSJ Scripture Refs: LXX.Exod.29.26