Bekhorot 48: words to know

נִתְחַיְּיבוּ נְכָסִים (nithayyvu nekhasim): The property became encumbered with the financial obligation. Rabbi Yehuda rules that the sons must pay because their father's estate became liened.
מִכְּדֵי (mikdei): Now consider; since; let us see. Rava uses this discourse particle to introduce an established legal premise.
עָרֵב (arev): A guarantor of a debt. Rava analyzes whether a debtor's estate can be held liable like a loan guarantor.
מִלְוֶה הַכְּתוּבָה בַּתּוֹרָה (milveh haktuvah baTorah): A financial obligation mandated by the Torah. The Gemara examines whether firstborn redemption is treated like a written contract.
מִלְוָה עַל פֶּה (milvah al peh): An oral loan without a promissory document. Rav Pappa rules that an oral debt may be collected from heirs but not buyers.