Luke 20:44 David therefore calleth him Lord, how is he then his son?
David in fact him a lord named? And how his son is he?
In the Greek, these two phrases are joined by a conjunction. It reads like two questions. Perhaps there was an answer in between. This is hidden in English because the "and" is translated as "then".
"David" is the Hebrew name.
The Greek word translated as "therefore" either emphasizes the truth of something ("certainly", "really") or it simply continues an existing narrative.
The term translated as "calleth" is like our word "call" means both "to summon" and also "to name." The sense is clearly that David "named" the Christ as his master.
The word translated as "him" is the Greek word commonly translated as third-person pronouns in English. The word means "the same" when used as an adjective. In the adverbial form, it means "just here" or "exactly there."
The word translated as "Lord" is the same word that is often translated as "Lord" or "the Lord" in the NT. It also means "lord", "master of the house," and "head of the family." It is the specific terms for the master of slaves or servants, but it was a common term of respect both for those in authority and who were honored. It was the term people used to address Christ, even though he had no formal authority. Today, we would say "boss" or "chief".
"How" is the adverb that means "how", "by any means", and "I suppose".
The verb "is he" here is the common form of "to be" in Greek. It means to have a certain characteristic or remain in a certain condition. It also equates terms or assigns characteristics.
The Greek word translated as "then" is used as the conjunction "and", but it also is used to add emphasis ("also"). In a series, it is best translated as "not only...but also." After words implying sameness "as".
The word translated as "his" is the Greek word commonly translated as third-person pronouns in English. The form his is possessive.
The word translated as "son" more generally means "child" or "children". It can refer to all offspring in later generations, just like "father" refers to all previous generations. Jesus also used it metaphorically to describe those who follow a way of thought or set of beliefs that descend from an individual. More about it in this article.
Δαυεὶδ (Proper name) "David" is from is from the Greek Dabid, which is the Greek form of the Hebrew name.
οὖν (adv) "Therefore" is oun, which means "certainly", "in fact", "really", "in fact," "so" and "then" (continuing a narrative), and "then" and "therefore."
αὐτὸν (adj sg masc acc) "Him" is from autos, which means "the same," and the reflexive pronouns, "myself", "yourself", "himself", "herself", "itself," or the oblique case of the pronouns, "him", "her," and "it." It also means "one's true self," that is, "the soul" as opposed to the body and "of one's own accord."
κύριον (noun sg masc acc) "Lord" is kyrios (kurios), which means "having power", "being in authority" and "being in possession of." It also means "lord", "master of the house," and "head of the family." --
καλεῖ (verb 3rd sg imperf ind act) "Calleth" is from kaleo, which means "call", "summon", "invite", "invoke", "call by name," and "demand."
καὶ (conj/adv) "And" is kai, which is the conjunction joining phrases and clauses, "and," or "but." After words implying sameness, "as" (the same opinion as you). Used in series, joins positive with negative "Not only...but also." Also used to give emphasis, "even", "also," and "just."
πῶς (adv/conj) "How" is pos, which means "how", "how in the world", "how then", "in any way", "at all", "by any mean", "in a certain way,"and "I suppose." --
αὐτοῦ (adj sg masc gen) "His" (adj sg masc acc) "Him" is autos, which means "the same," and the reflexive pronouns, "myself", "yourself", "himself", "herself", "itself," or the oblique case of the pronouns, "him", "her," and "it." It also means "one's true self," that is, "the soul" as opposed to the body and "of one's own accord." In the adverbial form, it means "just here" or "exactly there."
υἱός (noun sg masc nom) "The Son" is huios, which means a "son," and more generally, a "child." It is used generally to refer to any male descendant. --
ἐστιν; ( verb 3rd sg pres ind act) "Is" is eimi, which means "to be", "to exist", "to be the case," of circumstance and events "to happen", and "is possible." (The future form is esomai. The 3rd person present indicative is "esti.") --