x1 is the temporal direction of/toward solstice x2 (event or spacetime coordinates or season (usually specify year); default: Summer solstice) from origin/in reference frame x3 at location/for body x4 and with respect to orbit/sun x5.
This is a radial direction ('inward' relative to x2 and 'outward' relative to the solstice which is opposite to x2), but in a temporal sense. Given that, for a fixed body and orbit, seasons are usually(?) cyclic, this word will usually reference the temporal direction which points toward the referenced solstice of the specified type which is nearest to x3, unless the general pattern of behavior is being referenced or there is ambiguity/nondefinition (such as at the very moment of precisely the opposite solstice) or multiple x3s are specified such that they do not share a unique nearest solstice of the specified type or it does not matter or is abstract/general. Use-case example: You are taking a trip to Iceland but want to be somewhat warm. Your friend suggests going in November. You can reply that you want to visit at a time which is more Summer-solsticeward via this word (relying/capitalizing on the default value for x2). See also: "3 = x3 with respect to orbit/sun x4.">dornilteikezraifau".