1US Designating a mixture of hardened steel and a softer, stronger metal (especially iron) in which the steel is fused to a core made of the other metal, as "soft-centre steel", etc.
Soft-centre steel is a strong and resilient material with a hard-wearing surface. John Lane (1824–97) is credited with having first developed and patented a technique for making ploughshares from the material.
2 rare Designating a ploughshare consisting of soft metallic core and a hardened metallic surface, especially one made of soft centre steel; designating a plough possessing such a ploughshare.
3Of a chocolate or other confection: = "soft-centred".
4Revealing an essentially compassionate or sentimental nature.
1A soft filling inside a chocolate or other confection.
2A chocolate or other confection with a soft filling.
3A compassionate or sentimental nature, a tender heart, especially contrasting with a tough exterior.
Mid 19th century. From soft + centre.