In order to know what the meanings of words are we must let the Bible be its own dictionary.
Look at the context in which these words appear together, as well as individually. A concordance or Bible software word search is a good tool to use for this. The word search can tell you all of the places where they occur together, while the concordance can tell you how many times a given Hebrew or Greek word is used specifically for the word you’re researching.
In the case of corn, wine, and oil, you will find that together they represent the Gospel. Individually, corn is associated with Jesus or bread; wine is represented by the blood of Christ in some contexts, and God’s wrath in others; and oil is often pointing to the Holy Spirit.
When you study the Bible any conclusion you draw must 1) relate to the Gospel of Salvation, 2) have the validation from the Bible, and 3) be consistent or in agreement with everything else the Bible teaches concerning the nature of salvation.
Keep reading the Bible and searching the scriptures comparing scripture with scripture to find truth.