English, including: Sun signs in astrology Sign or signing, in communication: communicating via hand gestures, such as in sign language. Gang signal Sign, in Tracking (hunting): also known as Spoor (animal); trace evidence left on the ground after passage. A signboard. A sign, in common use, is an indication that a previously observed event is about to occur again Sign, in divination and religion: an omen, an event or occurrence believed to foretell the future Sign, in ontology and spirituality: a coincidence or surprising event thought to reveal divine will; see synchronicity Sign (linguistics): a combination of a concept and a sound-image described by Ferdinand de Saussure In mathematics, the sign of a number tells whether it is positive or negative. Also, the sign of a permutation tells whether it is the product of an even or odd number of transpositions. Signedness, in computing, is the property that a representation of a number has one bit, the sign bit, which denotes whether the number is non-negative or negative. A number is called signed if it contains a sign bit, otherwise unsigned. See also signed number representation Sign, in biology: an indication of some living thing's presence Medical sign, in medicine: objective evidence of the presence of a disease or disorder, as opposed to a symptom, which is subjective Sign (semiotics): the basic unit of meaning Information sign: a notice that instructs, advises, informs or warns people Traffic sign: a sign that instructs drivers; see also stop sign, speed limit sign, cross walk sign Sign, in a writing system: a basic unit. Similar terms which are more specific are character, letter or grapheme Commercial signage, including flashing signs, such as on a retail store, factory, or theatre Signature, in history: a handwritten depiction observed on a document to show authorship and will For marketing or advocacy purposes, a signage refers to the collective use of signs to convey a message. Christianity St. Augustine was the first man who synthesized the classical and Hellenistic theories of signs. For him a sign is a thing which is used to signify other things and to make them come to mind (De Doctrina Christiana (hereafter DDC) 1.2.2; 2.1.1). The most common signs are spoken and written words (DDC 1.2.2; 2.3.4-2.4.5). Although God cannot be fully expressible, Augustine gave emphasis to the possibility of God's communication with humans by signs in Scripture (DDC 1.6.6). Augustine endorsed