Conjunction
Two points sitting at, or close to, the same degree — the tightest aspect, read as a blending of whatever the two points represent.
A conjunction is the simplest aspect there is: two points close enough in degree, usually within a few degrees either way, to be treated as occupying the same spot on the wheel. Because they're not separated by any real distance, their two influences tend to be read together rather than compared or contrasted, more a merging than a meeting. A conjunction can involve the Sun and Moon, as it does at a new moon, or any two planets, or a planet and an angle like the ascendant, and what it means shifts entirely with which two points are involved. It's the aspect most people first learn to spot, since it needs no angle math beyond checking whether two numbers are close.