Would injecting be considered ingestion

Answer 1

No. Ingestion is eating.

Only if you inject the substance, in some way, into your oral cavity, like with a 'party' tool like those that force beer into your mouth. But, that is generally not considered true injection. That is usually done as a subcutaneous injection, like with a hypodermic needle. That is not ingestion because that typically refers to the oral cavity as the entry point and the target system as the digestive system that uses mechanical and chemical methods to breakdown substances so they can be absorbed into the blood stream. Since injections by-pass this system entirely it would not be proper to consider it as ingestion.