| PSI | • psi n. (Countable) The twenty-third letter of Classical and Modern Greek and the twenty-fifth letter of Old… • psi n. (Uncountable, parapsychology) A form of psychic energy. • psi sym. Pounds per square inch (an imperial unit of pressure). |
| SIB | • sib adj. Having kinship or relationship; related by same-bloodedness; having affinity; being akin; kindred. • sib n. Kindred; kin; kinsmen; a body of persons related by blood in any degree. • sib n. A kinsman; a blood relation; a relative, near or remote; one closely allied to another; an intimate companion. |
| SIC | • sic adv. Thus; thus written; used to indicate, for example, that text is being quoted as it is from the source. • sic v. To mark with a bracketed sic. • sic v. (Transitive) To incite an attack by, especially a dog or dogs. |
| SIF | • Sif prop.n. (Norse mythology) A golden-haired goddess associated with earth, mother of Ullr and wife of Thor. • SIF adj. (South African) disgusting (syphilitic). |
| SIG | • sig n. (Internet, informal) A signature, especially on emails or newsgroup postings. • sig n. (UK, dialectal, dated) Urine. • Sig prop.n. A male given name from German Siegfried. |
| SIK | • SIK adj. (Australian slang) excellent. |
| SIM | • sim n. (Informal) A simulation or simulator. • Sim prop.n. A male given name, diminutive of Simon and Simeon. • Sim prop.n. A Scottish surname transferred from the given name derived from the given name. |
| SIN | • sin n. (Theology) A violation of God’s will or religious law. • sin n. Sinfulness, depravity, iniquity. • sin n. A misdeed or wrong. |
| SIP | • sip n. A small mouthful of drink. • sip v. (Transitive) To drink slowly, small mouthfuls at a time. • sip v. (Intransitive) To drink a small quantity. |
| SIR | • sir n. A man of a higher rank or position. • sir n. A respectful term of address to a man of higher rank or position, particularly… • sir n. A respectful term of address to an adult male (often older), especially if his name or proper title is unknown. |
| SIS | • sis n. (Informal) Clipping of sister. • sis pron. (AAVE, slang) she. • SIs n. Plural of SI. |
| SIT | • sit v. (Intransitive, copulative, of a person) To be in a position in which the upper body is upright and supported… • sit v. (Intransitive, of a person) To move oneself into such a position. • sit v. (Intransitive, of an object) To occupy a given position. |
| SIX | • six num. A numerical value equal to 6; the number following five and preceding seven. This many dots: (••••••). • six n. A group or set with six elements. • six n. The digit or figure 6. |