| Term | Definition |
| HIGH SPIRED |
Said of a gastropod shell which is much higher than wide; see also: LOW SPIRED. See other gastropod shapes. |
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| LOW SPIRED |
Said of a gastropod shell which is much wider than high; see also: HIGH SPIRED. See other gastropod shapes. |
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| SPIRE | [need definition]. | |
| SPIRE ANGLE | The angle at which the whorls of a spire increase in size. See illustration: Composite Gastropod. | |
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| SPIRE WHORL | One turn (360 degrees) of the spire, exclusive of the BODY WHORL. | |
| SPIRE, INVOLUTE | The condition of having the POSTNUCLEAR WHORLS higher than, and enveloped by the NUCLEAR WHORLS; see also: SPIRE, SUNKEN. | |
| SPIRE, SUNKEN | The condition of having the POSTNUCLEAR WHORLS higher than the spire, or NUCLEAR WHORLS (the nuclear whorls are not hidden from view, as with an involute spire); see also: SPIRE, INVOLUTE. | |
| SPIRE | The cone of whorls produced, by the downward growth from the APEX, of shelled, non-symmetrical gastropods, including all whorls above the aperture. See illustration: Composite Gastropod. See also: SPIRE ANGLE. | |