### Black Hole:
A black hole is a region in space where gravity is so intense that nothing, not even light, can escape from it. It forms when a massive star collapses under its own gravity at the end of its life cycle. The event horizon is the boundary around a black hole, beyond which nothing can return. The core, or singularity, is a point where density and gravitational forces are infinitely strong, and known physics breaks down.

### Characteristics:
1. **Event Horizon**: The point beyond which no information or matter can escape.
2. **Singularity**: Central point with infinite density.
3. **Gravitational Pull**: Extremely strong, causing time dilation and space curvature.
4. **Types**: Stellar (collapsed stars), supermassive (galactic centers), and intermediate.

### Wormhole:
A wormhole, or Einstein-Rosen bridge, is a hypothetical tunnel-like structure connecting two separate points in spacetime. Unlike black holes, wormholes are theoretical constructs predicted by the equations of general relativity and are not yet observed.

### Characteristics:
1. **Two Mouths**: Entrances that connect different points in spacetime.
2. **Throat**: The passage linking the two mouths.
3. **Stability**: Requires exotic matter with negative energy density to remain open, which is not yet proven to exist.
4. **Potential for Time Travel**: Could theoretically allow for faster-than-light travel and shortcuts through spacetime.

### Differences:
Black holes are massive gravitational wells from collapsed stars, whereas wormholes are theoretical spacetime tunnels that connect disparate regions of the universe. Black holes are observed phenomena, while wormholes remain speculative.