ground rule 
noun
1 (usually ground rules) A basic principle: some ground rules for assessing new machines...
- Before an interview, Johnson laid down the ground rule that he didn't want to talk about his Seattle days.
- My first ground rule is always to tell the truth.
- The ground rule on that subject would be never to make familiarity with one's earlier works necessary for enjoying or appreciating the current one.
2 Baseball A rule relating to the limits of play on a particular field.He learned the hard way about a Wrigley Field ground rule....
- By establishing ground rules, the playing field can be leveled for all participants.
- Under the ground rules of the Astrodome, the ball was in play.
- Enceladus
- encephalic
- encephalin
- encephalisation
- encephalitic
- encephalitis
- encephalitis lethargica
- encephalitogenic
- encephalization
- encephalization quotient
- encephalo-
- encephalogram
- encephalograph
- encephalographic
- encephalography
- encephalomyelitis
- encephalon
- encephalopathy
- enchain
- enchainment
- enchant
- enchantedly
- enchanter
- enchanter's nightshade
- enchanting