Prone has two very different senses: lying face down, or likely to suffer or do something (usually bad). Prostrate also means lying face down, but it carries a stronger note of submission, collapse, or being overcome — think "prostrate with grief," not just lying on the floor.
The core difference
Prone is the neutral word for face-down or likely-to; prostrate adds weight — collapse, worship, or being overwhelmed.
- prone — lying face down, or likely to do/suffer something: this coast is prone to flooding.
- prostrate — lying flat face down, often in submission, or overwhelmed by grief or exhaustion: she was left prostrate with grief.
How to tell them apart
Both words can describe a body lying face down, but reach for prostrate when there's an emotional or physical collapse behind the position — grief, exhaustion, or deliberate submission, as in pilgrims who prostrate themselves before a shrine. Prone does the plainer job: it simply names the position, or, in its more common modern use, describes a tendency, as in someone prone to exaggeration.
A useful memory hook: prostrate sounds like "prostrated by" something — grief, illness, worship — while prone's other sense, "prone to," pairs naturally with a habit or risk rather than a collapse.
