Here is an interesting, extended defining of the term seed, by Mr. Zodhiates:
zera`: Seed- A masculine noun meaning sowing, seed, descendants, offspring, children, and posterity. The literal use of the word indicates seed of the field (i.e., seed planted in the field). When Israel entered Egypt, Joseph instructed the Israelites to keep four-fifths of the crop as seed to plant in their fields and to serve as food for them (Ge 47:24); the season for planting seed was guaranteed by God to continue without fail (Ge 8:22); and successful, abundant harvests were promised right up until the sowing season if Israel followed the Lord's laws and commands (Lev 26:5). God had created the seed of the field by decreeing that plants and trees would be self-perpetuating, producing their own seed (Ge 1:11) and that the seed-producing plants would be edible (Ge 1:29). Manna, the heavenly food, resembled coriander seed (Ex 16:31). Any seed could be rendered unclean and not usable if a dead body fell on it after the seed had been moistened (Lev 11:38).
The noun is used to describe the seed (i.e., the offspring) of both people and animals. The seed of Judah and Israel would be united and planted peacefully in the land together with animals in a pleasant setting (Je 31:27). Seed can be translated as son (i.e., seed as when God gives Hannah a promise of a son [1Sa 1:11]). The seed of a woman mentioned in Ge 3:15 is her offspring.
The offspring of humans is described many times by this word. Hannah was given additional children to replace Samuel, whom she gave to the Lord's service (1Sa 2:20). The most important seed that the author of Genesis describes is the seed of Abraham, the promised seed, referring to Isaac, Jacob, and his twelve sons (Ge 12:7; 15:3). The author of Genesis uses the word twenty-one times in this setting (Ex 32:13; Dt 1:8). The seed of the royal line of David was crucial to Israel's existence, and the term is used nine times to refer to David's offspring or descendants (2Sa 7:12). In a figurative sense, seed refers to King Zedekiah and perhaps to Israelites of royal lineage, whom Nebuchadnezzar established in Jerusalem (Eze 17:5). Royal lines or seed were found outside Israel, such as in Edom, where Hadad belonged to the royal line (1Ki 11:14), and in Judah, where the wicked Athaliah attempted to destroy the royal seed (2Ki 11:1; 25:25; Je 41:1).
The seed or offspring of a particular nation can be characterized in moral and religious terms as well. Three verses stand out: The seed of Israel was called a holy seed (Ezr 9:2; Isa 6:13); and, in the case of Ezr 9:2, the seed corrupted itself by mixing with the peoples around them. The seed of Israel is a seed of God or a divine seed (Mal 2:15) through its union with God (cf. 2Pe 1:4). An offspring could be described as deceitful and wicked (Ps 37:28; Isa 57:4). It was important in Israel to prove that one's origin or seed stemmed from an Israelite ancestor, for some Israelites and Israelite priests who returned from exile could not show their origin (Ezr 2:59). The word also refers to the seed or posterity of the Messiah (Isa 53:10).
zera`: Seed- A masculine noun meaning sowing, seed, descendants, offspring, children, and posterity. The literal use of the word indicates seed of the field (i.e., seed planted in the field). When Israel entered Egypt, Joseph instructed the Israelites to keep four-fifths of the crop as seed to plant in their fields and to serve as food for them (Ge 47:24); the season for planting seed was guaranteed by God to continue without fail (Ge 8:22); and successful, abundant harvests were promised right up until the sowing season if Israel followed the Lord's laws and commands (Lev 26:5). God had created the seed of the field by decreeing that plants and trees would be self-perpetuating, producing their own seed (Ge 1:11) and that the seed-producing plants would be edible (Ge 1:29). Manna, the heavenly food, resembled coriander seed (Ex 16:31). Any seed could be rendered unclean and not usable if a dead body fell on it after the seed had been moistened (Lev 11:38).
The noun is used to describe the seed (i.e., the offspring) of both people and animals. The seed of Judah and Israel would be united and planted peacefully in the land together with animals in a pleasant setting (Je 31:27). Seed can be translated as son (i.e., seed as when God gives Hannah a promise of a son [1Sa 1:11]). The seed of a woman mentioned in Ge 3:15 is her offspring.
The offspring of humans is described many times by this word. Hannah was given additional children to replace Samuel, whom she gave to the Lord's service (1Sa 2:20). The most important seed that the author of Genesis describes is the seed of Abraham, the promised seed, referring to Isaac, Jacob, and his twelve sons (Ge 12:7; 15:3). The author of Genesis uses the word twenty-one times in this setting (Ex 32:13; Dt 1:8). The seed of the royal line of David was crucial to Israel's existence, and the term is used nine times to refer to David's offspring or descendants (2Sa 7:12). In a figurative sense, seed refers to King Zedekiah and perhaps to Israelites of royal lineage, whom Nebuchadnezzar established in Jerusalem (Eze 17:5). Royal lines or seed were found outside Israel, such as in Edom, where Hadad belonged to the royal line (1Ki 11:14), and in Judah, where the wicked Athaliah attempted to destroy the royal seed (2Ki 11:1; 25:25; Je 41:1).
The seed or offspring of a particular nation can be characterized in moral and religious terms as well. Three verses stand out: The seed of Israel was called a holy seed (Ezr 9:2; Isa 6:13); and, in the case of Ezr 9:2, the seed corrupted itself by mixing with the peoples around them. The seed of Israel is a seed of God or a divine seed (Mal 2:15) through its union with God (cf. 2Pe 1:4). An offspring could be described as deceitful and wicked (Ps 37:28; Isa 57:4). It was important in Israel to prove that one's origin or seed stemmed from an Israelite ancestor, for some Israelites and Israelite priests who returned from exile could not show their origin (Ezr 2:59). The word also refers to the seed or posterity of the Messiah (Isa 53:10).