---
book: 2
part: "definitions"
source: "https://scaife.perseus.org/reader/urn:cts:greekLit:tlg1799.tlg001.perseus-eng2:2"
license: "CC-BY-SA-4.0"
---

# Book II Definitions

## Definition 1

Any rectangular parallelogram is said to be *contained* by the two straight lines containing the right angle.

## Definition 2

And in any parallelogrammic area let any one whatever of the parallelograms about its diameter with the two complements be called a *gnomon.*