The "Run" Universe - Run out of, Run into, Run over

The line at the coffee shop isn't moving. Up ahead, the barista looks stressed. He leans over the counter and says to the person in front, Sorry, we've just run out of oat milk.[TRANS]

A collective sigh. This feeling is universal. It’s the core of our first “run” verb.

run out of isn't just about something being “gone.” It’s about a supply being depleted through a process. The verb run gives it a sense of forward momentum, like a countdown hitting zero. Your phone battery doesn't just disappear; it runs out over hours of use.

So, run out of is when momentum empties a container. But what happens when that momentum hits a wall instead? Or, more likely, another person?

This is run into. It’s the verb for an unplanned collision. While it can be physical, like a car hitting a pole, its most powerful use is social. It describes an unexpected encounter with someone you know.

The Physics of Momentum

Stop memorizing these as separate phrases. The secret is that run isn't about your legs. In phrasal verbs, run is about uncontrolled forward energy. It’s a vector. Once you see that, the preposition tells you everything.

Energy + out of = The energy drains a resource to zero.
Energy + into = The energy collides with an obstacle (a person, a problem).
Energy + over = The energy moves above and across something, usually with force. Think of a car running over a speed bump, or worse, someone's phone.

The Golden Rule: Don't ask “What does run into mean?” Ask, “Where is the momentum of run going?” The preposition gives you the answer. This is the key that unlocks the entire system, not just for run, but for hundreds of other phrasal verbs.