The Greek noun teras (τέρας) refers to a wonder or prodigy — an event so astonishing that it causes amazement. In the New Testament, teras almost always appears paired with sēmeion (sign) as the phrase 'signs and wonders' (sēmeia kai terata). While sēmeion emphasizes the signifying meaning, teras emphasizes the astonishment produced by the event.
The pairing of sēmeia kai terata runs throughout redemptive history. The Exodus miracles were described this way (Acts 7:36). The apostolic mission was authenticated by signs and wonders (Acts 2:22; Hebrews 2:4). Yet Jesus warned that false prophets would perform signs and wonders to deceive even the elect (Matthew 24:24). The criterion for evaluating terata is not the wonder itself but conformity to revealed truth — a miracle that leads away from God is rejected regardless of its power. Genuine signs and wonders confirm the proclaimed Word; they do not replace it.