Final answer:
The antonym for 'Elementary' is 'Advanced', indicating a more complex and developed level in contrast to basic or foundational aspects. The term 'advanced' relates to sophistication and surpasses the rudimentary or primary stage represented by 'elementary'.
Step-by-step explanation:
The antonym for 'Elementary' which suggests something basic or fundamental in nature is 'Advanced'. Advanced refers to a stage of knowledge or development that is more complex and surpasses the elementary or initial level. For example, in the context of learning, an elementary understanding of mathematics might include basic arithmetic, while an advanced understanding would encompass complex algebra or calculus.
Within the realm of chemistry and chemical substances, similar differentiation takes place between elementary substances which are pure and cannot be broken down into simpler substances, and more complex compounds. The word 'elementary' denotes simplicity and the foundational phase of something, while 'advanced' suggests complexity, specialization, and a higher degree of sophistication or development after the elementary phase.