| SDP | |
| —abbreviation for | |
| Social Democratic Party | |
| a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question. |
| an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle. |
| SDP software development plan |