inject

To push or pump (something, especially fluids) into a cavity or passage.

The nurse injected a painkilling drug into the veins of my forearm.

To introduce (something) suddenly or violently.

Punk injected a much-needed sense of urgency into the British music scene.

Caesar also, then hatching tyranny, injected the same scrupulous demurs.

To administer an injection to (someone or something), especially of medicine or drugs.

Now lie back while we inject you with the anesthetic.

to inject the blood vessels

To take or be administered something by means of injection, especially medicine or drugs.

It's been a week since I stopped injecting, and I'm still in withdrawal.

To introduce (code) into an existing program or its memory space, often without tight integration and sometimes through a security vulnerability.

Yes, you'll have to use CreateRemoteThread to "inject code" if you want information like the current directory of a process (at least on NT 3.5x).

As soon as a virus programmer discovers that some popular ActiveX thing has a bug that can be exploited, e.g. with controlled crashes to inject code, it's going to be a disaster.