The definitions I grew up on (and still use):
Jam: made with whole fruit, usually fresh or frozen, has a jelling agent (pectin or gelatin) for the spreadable texture
Jelly: made with juice or strained fruit pulp (therefore seeds and skins removed, some pulp may be present in homemade stuff), juice can be storebought or homemade if you use a cheesecloth to strain out the juice, has a jelling agent (pectin or gelatin) for spreadable texture/consistency.
Preserves: fruit that has been minimally processed (relative to jams, which typically require cooking the fruit into a sauce and sometimes mashing before adding the jelling agent), therefore has whole fruit or large chunks of fruit. NO jelling agent but typically has some sugar to aid in preservation. Preserves are a way of storing fruit that you haven't "decided" what to do with (all purpose fruit), or have preserved for use as pie filling, sauce, etc (i.e., things you don't want jelled like jams and jelly). Preserves are also a bit of a catch-all term for home canned goods, both sweet and savory, and "preserves" sometimes refers to minimally cooked stuff like canned peaches (and other fruit or veg that were only blanched and not cooked) in water or light syrup.
Compote: similar to preserves it consists of whole or chunks of fruit without a jelling agent. Compote may be cooked more than preserves, so that it forms more of a sauce. May have additional spices/flavorings. It still has sugar added but typically less sugar than jams/jellies, which use sugar to help preserve the fruit. It's less common to home can compote, but it can be done
Conserves: for clarity, these are typically not just dried fruit/nuts, they are jams/preserves with dried fruits and nuts added to them. Dried citrus dont typically count as conserves, see marmalade below. I'm not as familiar with conserves, as they aren't common where I grew up or in my family. Like the word "preserves", "conserves" is sometimes used as a generic catch-all term for home canned goods
Marmalades: citrus based preserves with the peel. Marmalade typically doesnt have a jelling agent, but some might. The biggest thing is that they are 1) citrus based, and 2) contains fresh, dried, or candied citrus peel. Marmalade can have other fruit added (like peach), but their base is always citrus. The bits of peel are chewy and kinda bitter.
Fruit Butters: made from fruit that has been cooked and processed (mashing, blending, etc) into a smooth consistency, kinda like apple sauce but much thicker and less watery. No jelling agent (pectin or gelatin) is added. Spices and other flavorings are common, but not required. Apple is the most common fruit butter, but peaches, pears, etc can also be made into fruit butter.
Chutney: less sugar (but may still be sweet), intended for use with savory food as a sauce/topping/relish, may have vinegar or spices added
Curd: citrus (especially lemon) is by far the most common fruit curd, though you could make it with other fruits. Curds rely on egg yolks for its texture, and are therefore similar to custard in terms of texture and use. Curd is not typically home canned, you would either made it fresh or buy it commercially canned. Curds typically include zest, but are smooth in texture (no fruit chunks, little to no pulp)
