ɪn dʒˌiːoʊmˈɛtɹɪk mˈɛʒɚ θˈiəɹi sˈʌtʃ ɐ smˈuːð kˈɜːv æz ðə sˈɜːkəl ðæt kæn biː ɐpɹˈɑːksɪmˌeɪɾᵻd baɪ smˈɔːl stɹˈeɪt sˈɛɡmənts wɪð ɐ dˈɛfɪnət lˈɪmɪt ɪz tˈɜːmd ɐ ɹˈɛktɪfˌaɪəbəl kˈɜːv.
In geometric measure theory such a smooth curve as the circle that can be approximated by small straight segments with a definite limit is termed a rectifiable curve.