A component for a turbine engine (10, 102), wherein the turbine engine (10, 102) is selected from the group consisting of gas turbine engines, unducted turbine engines, turboprop engines, turboshaft engines, turbofan engines and turbojet engines; wherein the component is a blade or vane, the component comprising: a wall bounding an interior and defining an exterior surface extending between a leading edge and a trailing edge to define a chordwise direction, and radially between a root and a tip to define a spanwise direction; and a spar assembly (140, 240, 340, 440, 540) comprising: a hub (145, 245, 345, 445, 545); a metallic spar (141, 241, 341, 441, 541) extending from the hub (145, 245, 345, 445, 545) in the spanwise direction into the interior, the metallic spar (141, 241, 341, 441, 541) defining a socket (252, 352, 452, 552) extending in the spanwise direction, the socket having at least one side opening (254, 354, 454, 554a, 554b); a composite spar (142, 242, 342, 442, 542) extending in the spanwise direction between a spar root (146, 246, 346, 446, 546) and a spar tip, at least a portion of the spar root (146, 246, 346, 446, 546) located in the socket (252, 352, 452, 552); and a stiffener (143, 243, 343, 443, 543, 543a, 543b) bonded to at least one of the wall, the metallic spar (141, 241, 341, 441, 541), or the composite spar (142, 242, 342, 442, 542), at least a portion of the stiffener extending at least in part through the at least one side opening (254, 354, 454, 554a, 554b). a wall bounding an interior and defining an exterior surface extending between a leading edge and a trailing edge to define a chordwise direction, and radially between a root and a tip to define a spanwise direction; and a spar assembly (140, 240, 340, 440, 540) comprising: a hub (145, 245, 345, 445, 545); a metallic spar (141, 241, 341, 441, 541) extending from the hub (145, 245, 345, 445, 545) in the spanwise direction into the interior, the metallic spar (141, 241, 341, 441, 541) defining a socket (252, 352, 452, 552) extending in the spanwise direction, the socket having at least one side opening (254, 354, 454, 554a, 554b); a composite spar (142, 242, 342, 442, 542) extending in the spanwise direction between a spar root (146, 246, 346, 446, 546) and a spar tip, at least a portion of the spar root (146, 246, 346, 446, 546) located in the socket (252, 352, 452, 552); and a stiffener (143, 243, 343, 443, 543, 543a, 543b) bonded to at least one of the wall, the metallic spar (141, 241, 341, 441, 541), or the composite spar (142, 242, 342, 442, 542), at least a portion of the stiffener extending at least in part through the at least one side opening (254, 354, 454, 554a, 554b). a hub (145, 245, 345, 445, 545); a metallic spar (141, 241, 341, 441, 541) extending from the hub (145, 245, 345, 445, 545) in the spanwise direction into the interior, the metallic spar (141, 241, 341, 441, 541) defining a socket (252, 352, 452, 552) extending in the spanwise direction, the socket having at least one side opening (254, 354, 454, 554a, 554b); a composite spar (142, 242, 342, 442, 542) extending in the spanwise direction between a spar root (146, 246, 346, 446, 546) and a spar tip, at least a portion of the spar root (146, 246, 346, 446, 546) located in the socket (252, 352, 452, 552); and a stiffener (143, 243, 343, 443, 543, 543a, 543b) bonded to at least one of the wall, the metallic spar (141, 241, 341, 441, 541), or the composite spar (142, 242, 342, 442, 542), at least a portion of the stiffener extending at least in part through the at least one side opening (254, 354, 454, 554a, 554b).