should Definition

1. Expressing: obligation, duty or recommendation; ought to.

Example: You should brush your teeth regularly
2. Expressing: likelihood or probability.

Example: He should have left by now
3a. Expressing: condition;

Example: If she should die before you, what would happen?
3b. Expressing:the consequence of a condition.

Example: I should never be able to live with myself if that happened
4. Expressing:a past tense of shall in reported speech. See note at shall.

Example: I told them I should be back soon
5. Expressing: statements in clauses with that, following expressions of feeling or mood.

Example: It seems odd that we should both have had the same idea
6. Expressing:doubt or polite indirectness in statements

Example: I should imagine he's left
Example: I should think I'll get the job
Example: I should like to thank you all for coming.
7. literary
Expressing:purpose.
Example: in order that we should not have to leave