like any rule of thumb
1Rule of thumb — Rule Rule, n. [OE. reule, riule, OF. riule, reule, F. r[ e]gle, fr. L. regula a ruler, rule, model, fr. regere, rectum, to lead straight, to direct. See {Right}, a., and cf. {Regular}.] 1. That which is prescribed or laid down as a guide for… …
2Rule — Rule, n. [OE. reule, riule, OF. riule, reule, F. r[ e]gle, fr. L. regula a ruler, rule, model, fr. regere, rectum, to lead straight, to direct. See {Right}, a., and cf. {Regular}.] 1. That which is prescribed or laid down as a guide for conduct… …
3Rule joint — Rule Rule, n. [OE. reule, riule, OF. riule, reule, F. r[ e]gle, fr. L. regula a ruler, rule, model, fr. regere, rectum, to lead straight, to direct. See {Right}, a., and cf. {Regular}.] 1. That which is prescribed or laid down as a guide for… …
4Rule of the road — Rule Rule, n. [OE. reule, riule, OF. riule, reule, F. r[ e]gle, fr. L. regula a ruler, rule, model, fr. regere, rectum, to lead straight, to direct. See {Right}, a., and cf. {Regular}.] 1. That which is prescribed or laid down as a guide for… …
5Rule of three — Rule Rule, n. [OE. reule, riule, OF. riule, reule, F. r[ e]gle, fr. L. regula a ruler, rule, model, fr. regere, rectum, to lead straight, to direct. See {Right}, a., and cf. {Regular}.] 1. That which is prescribed or laid down as a guide for… …
6As a rule — Rule Rule, n. [OE. reule, riule, OF. riule, reule, F. r[ e]gle, fr. L. regula a ruler, rule, model, fr. regere, rectum, to lead straight, to direct. See {Right}, a., and cf. {Regular}.] 1. That which is prescribed or laid down as a guide for… …
7Board rule — Rule Rule, n. [OE. reule, riule, OF. riule, reule, F. r[ e]gle, fr. L. regula a ruler, rule, model, fr. regere, rectum, to lead straight, to direct. See {Right}, a., and cf. {Regular}.] 1. That which is prescribed or laid down as a guide for… …
8Caliber rule — Rule Rule, n. [OE. reule, riule, OF. riule, reule, F. r[ e]gle, fr. L. regula a ruler, rule, model, fr. regere, rectum, to lead straight, to direct. See {Right}, a., and cf. {Regular}.] 1. That which is prescribed or laid down as a guide for… …
918-Electron rule — The 18 electron rule is a rule of thumb used primarily in transition metal chemistry for characterizing and predicting the stability of metal complexes. Valence shells of a transition metal can accommodate 18 electrons: 2 in each of the five d… …
10Slide rule — For other uses, see Slide rule (disambiguation). A typical ten inch student slide rule (Pickett N902 T simplex trig). The slide rule, also known colloquially as a slipstick,[1] is a mechanical analog computer. The slide rule is used primarily for …
