ἀκανθῶν [8 verses](noun pl fem gen) "Thorns" is akantha, which means "thorn", "prickle," or "any thorny or prickly plant." It is also a metaphor for a "thorny" question. -- The Greek words translated as "thorns" and "thistles" both mean any type of thorny plant. Two different words are used because this is a reference to Gen 3:18, where two different Hebrew words are used. This means that two different Greek words are used in the Septuagint, the Greek OT. The same exact ones used here. In Jewish tradition, thorns did not exist in the original creation, but were created after humanity's fall.