Numbers 13:33 And there we saw the giants (Heb. nĕphiyl), the sons of Anak, which come of the giants (Heb. nĕphiyl): and we were in our own sight as grasshoppers, and so we were in their sight.
Deuteronomy 2:10-11 The Emims dwelt therein in times past, a people great, and many, and tall, as the Anakims; Which also were accounted giants (Heb. rapha' ), as the Anakims; but the Moabites call them Emims.
Deuteronomy 2:20-21 (That also was accounted a land of giants (Heb. rapha' ): giants (Heb. rapha' ) dwelt therein in old time; and the Ammonites call them Zamzummims; A people great, and many, and tall, as the Anakims; but the LORD destroyed them before them; and they succeeded them, and dwelt in their stead:
The giants in Numbers were nephilim and, according to the verse, the sons of Anak were nĕphiyl.
In Deuteronomy, the word used is not nĕphiyl ... it is rapha' . Whether rapha' or nĕphiyl, they are related. Scripture does not indicate how they are related, but we know from Numbers sons of Anak are referred to as nĕphiyl and in Deuteronomy, the zamzummims were as tall as the Anakims (sons of Anak) and the zamzummims are referred to as rapha' .
nĕphiyl = nephilim
rapha' = rephaim
Og was a rapha' ... Deuteronomy 3:11 For only Og king of Bashan remained of the remnant of giants (rapha' ); behold, his bedstead was a bedstead of iron; is it not in Rabbath of the children of Ammon? nine cubits was the length thereof, and four cubits the breadth of it, after the cubit of a man.
In 2 Samuel we have another record of rapha' :
2 Samuel 21:
18 And it came to pass after this, that there was again a battle with the Philistines at Gob: then Sibbechai the Hushathite slew Saph, which was of the sons of the giant (rapha' ).
19 And there was again a battle in Gob with the Philistines, where Elhanan the son of Jaareoregim, a Bethlehemite, slew the brother of Goliath the Gittite, the staff of whose spear was like a weaver's beam.
20 And there was yet a battle in Gath, where was a man of great stature, that had on every hand six fingers, and on every foot six toes, four and twenty in number; and he also was born to the giant (rapha' ).
21 And when he defied Israel, Jonathan the son of Shimea the brother of David slew him.
22 These four were born to the giant (rapha' ) in Gath, and fell by the hand of David, and by the hand of his servants.