Which term does not fit with the others in real estate?

Marketable title is the correct choice here because it refers to a type of property title that is free from significant defects and is legally sufficient to be sold to a buyer. This term specifically relates to the quality and condition of a title in terms of its salability, ensuring that the seller has the legal right to transfer ownership without any issues.

In contrast, title insurance, abstract of title, and deed of trust are all tools or documents related to the conveyance and financing of real estate. Title insurance protects against losses resulting from defects in the title, while an abstract of title is a summary that outlines the history of ownership and claims against the property. A deed of trust, on the other hand, is a legal document used in real estate transactions that secures a loan by transferring the title of the property to a trustee until the borrower pays their debts.

Thus, while marketable title defines a quality of a title, the other terms involve processes or protective measures related to property ownership and financing. This distinction clarifies why marketable title does not fit with the others.