tip-over
Synonym discussion
Sense: phrasal verb/1
All four describe something moving from upright to a fallen position, but differ in cause, degree, and typical object. 'Knock over' (informal) always implies an external force hitting the object: 'The cat knocked over the vase.' 'Overturn' (more formal) suggests a complete turning upside down, often with visible effort: 'Protesters overturned a police car.' 'Topple' adds the idea of unsteadiness and slow fall, especially of tall objects: 'The pile of boxes toppled slowly.' 'Capsize' is restricted to boats and ships in water. 'Tip over' is the most general — it covers both accidental and intentional falls, sideways or upside down, and works for everything from a coffee cup to a truck.
Common collocations
Etymology
'Tip' comes from Middle English 'tippen', meaning to tilt or knock down, related to Old English 'typp' (top, summit) — so the image is that the top of an object falls, taking the rest down. 'Over' adds the sense of falling sideways. The phrasal verb 'tip over' appears in the 16th century, originally for carts and wagons that tilted and spilled their loads.