https://www.poetryfoundation.org/resources/learning/glossary-terms/detail/spondee
Spon·dee from the Free Dictionary
(spŏn′dē′)
n.
A metrical foot consisting of two long or stressedsyllables.
[Middle English sponde, from Old French spondee, fromLatin spondēum, from neuter of spondēus, of libations,spondaic, from Greek spondeios, from spondē, libation(from its use in songs performed at libations); see spend-in Indo-European roots.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
How my heart sings 