pi

noun (pi; the Greek letter π)

«pi» in the English dictionary: everyday and in Jewish tradition — its meanings, how the lessons use it, and examples, each with its tree on Mova.

Everyday

Pi is a special number, about 3.14, that links the distance around a circle to the distance across it. tree →
Pi (π) is also a letter of the Greek alphabet. tree →
Pi can also be a shrill, high sound, like the noise of a pipe. tree →

In the lessons

In maths: used with circles: circumference and area; π ≈ 3.14 or 22/7; its digits go on forever without repeating. In science: used to work out wheels, planets' orbits and round things. In everyday life: «Pi Day» fun in schools; people try to remember many digits of pi.

Examples

Use 3.14 for pi. tree →
The circumference is pi times the diameter. tree →
Area of a circle is pi times the radius times the radius. tree →
The symbol for pi is π. tree →
The digits of pi go on forever: 3.14159… tree →
A wheel 1 meter across moves about 3.14 meters in one turn. tree →
Some people can remember a hundred digits of pi. tree →
Our class ate pie on Pi Day. tree →
On he ran, and louder grew the sounds of pipe and drum: pi-pi-pi, pi-pi-pi, pi-pi-pi . . .zum, zum, zum, zum. tree →

Note

Pi ≈ 3.14 or 22/7. Circumference = pi × diameter; area = pi × radius × radius. Trap: do not mix radius and diameter (diameter = 2 × radius). Homophone: pie (food); the joke «pi» and «pie» is common. Pi is the same for every circle, big or small.

In Jewish tradition

Pi-hahiroth is where the Israelites camped just before the sea split. Pi-beseth is an Egyptian city whose young men Ezekiel says will fall by the sword.

Interpretation. The rabbis said God led them to Pi-hahiroth on purpose, so Pharaoh would think they were trapped and follow them to the sea.

Examples

'Speak unto the children of Israel, that they turn back and encamp before Pi-hahiroth, between Migdol and the sea, before Baal-zephon, over against it shall ye encamp by the sea. (Torah EXO.14.2, JPS 1917) tree →
And the Egyptians pursued after them, all the horses and chariots of Pharaoh, and his horsemen, and his army, and overtook them encamping by the sea, beside Pi-hahiroth, in front of Baal-zephon. (Torah EXO.14.9, JPS 1917) tree →
The young men of Aven and of Pi-beseth shall fall by the sword; and these cities shall go into captivity. (Prophets EZK.30.17, JPS 1917) tree →

Note

On Mova

Trees and pragmatics of «pi» in the school dictionary: every meaning and example parsed by Mova, with its dependency tree and frames.
«pi» in the school dictionary on Mova free.
Trees and pragmatics of «pi» in the Judaism dictionary: every meaning and example parsed by Mova, with its dependency tree and frames.
«pi» in the Judaism dictionary on Mova free.

This page in Markdown → https://md.dictionary.elamur.ai/free/en/english/pi/