Arm (physical) - Vine's Expository Dictionary of New Testament Words
Arm (physical)[ 1,,G43, ankale ]
used in the plural, in Luke 2:28, originally denoted the curve, or the inner angle, of the arm." The word is derived from a term signifying "to bend, to curve;" the Eng. "angle" is connected.
Note: Enankalizomai (en, "in," and a verb akin to No. 1), "to take into the arms, to embrace," is used in Mark 9:36; Mark 10:16, of the tenderness of Christ towards little children.
[ 2,,G1023, brachion ]
"the shorter part of the arm, from the shoulder to the elbow," is used metaphorically to denote strength, power, and always in the NT of the power of God, Luke 1:51; John 12:38; Acts 13:17; frequently so in the OT, especially in Deuteronomy, the Psalms and Isaiah; See, e.g., Deuteronomy 4:34; Deuteronomy 5:15; Psalms 44:3; Psalms 71:18, where "strength" is, lit., "arm;" Psalms 77:15; Isaiah 26:11, where "hand" is, lit., "arm;" Isaiah 30:30; Isaiah 40:10-Isaiah 40:11, etc.