ooidal vs ovoid

ooidal

adj

  • Egg-shaped. 

  • Oolitic. 

ovoid

adj

  • Egg-shaped; shaped like an oval, but more tapered at one end; ovate. 

  • Shaped like an oval. 

noun

  • Something that is oval in shape. 

How often have the words ooidal and ovoid occurred in a corpus of books? (source: Google Ngram Viewer )