Questions: injection made directly into a vein

The answer is "intravenous."

Explanation:

• The clue "injection made directly into a vein" refers to a method of delivering medication or fluids directly into the bloodstream through a vein.
• The term for this method is "intravenous," often abbreviated as IV.
• "Intravenous" comes from the Latin words "intra," meaning within, and "venous," meaning related to veins.

Summary: The term for an injection made directly into a vein is "intravenous."