Unicycle, bicycle, tricycle, quadbike.
All as easy as one two three. Well, one two three four, anyway.
Uni means one, as in unicorn (one horn) uniform (one sort of clothes, probably ugly) and Unicef (hang on, though, not as in Unicef: that stands for United Nations International Children's Emergency Fund. But never mind).
Bi means two, as in binary (which is counting using only two numbers, zero and one. It's what computers do) and binoculars (two eyepieces) and biology...
...hang on, though. I'm sure my biology teacher told me that biology was the two sciences of botany and zoology put together. But the dictionary says biology is actually from the Greek word for life, bios.
Well, tri is certainly the same word as three. So a triangle has three sides, a trident has three prongs, and a third in music describes two notes which are...
...two notes apart.
Ah yes, but quad, that's such an odd word that it MUST always mean four. Like a quadrille is a square dance, and a quadrilateral has four sides, and a quaternary fever is one which keeps coming back every...
Okay, I give up! These people just can't COUNT, can they?!
Word to use today: bilge (which is what we used to call biology at school). It really means the bit of a boat where the hull goes inwards at the bottom, and also the dirty water that tends to end up there. Bilge also, of course, means rubbish, and is probably linked to the word bulge.