entailment

Harper Leeの 'To Kill a Mockingbird' を読み始めました。 このタイトルはユニークなので見覚えがあります。　殺人事件を連想しますが、
その内容は全く知りません。

My special knowledge of the Cunningham tribe--one branch, that is--was gained from events of last winter. Walter's father was one of Atticus's clients. After a dreary conversation in our livingroom one night about his entailment, before Mr. Cunningham left he said, "Mr. Finch, I don't know when I'll ever be able to pay you."

語り手はこの時は6歳の少女で Atticusはその父親です。
"entailment" の意味を辞書で調べましたが、何か哲学的な意味の説明が多く、引用した小説での意味かどうか怪しい？

例えば、Vocabulary.comに次の記述がありました。
In logic, an entailment is the relationship between sentences whereby one sentence will be true if all the others are also true. Want a less-dry-sounding, real-life example? How about this: Being a good student, for instance, is an entailment of attending classes, learning the material, and keeping up with assignments. An old-fashioned definition of entailment is a set of limitations that restrict the ways property can be bequeathed to heirs.
前半の説明が多くの辞書に記載されている内容とほぼ同じで、何のこっちゃ？で意味がよく分かりません。しかし最後の文に、古い時代の意味に触れています。これをヒントにさらに別の辞書を見ると、次の説明を見つけました。

・Merriam-Webster: the act or an instance of restricting the inheritance of property to the owner's lineal descendants or to a particular class thereof: They came from places where for centuries, economic development had been hindered because nobles controlled most of the land. Which was passed down by primogeniture and entailment, generation after generation, to the eldest son.

この意味なら、引用した小説での場面に当てはまりそうだ。