Supremacy. It was one word, and it did not require much explanation. It was self evident. The tenet that Lex chose, after considering his numerous affinities and abilities and strengths, the tenet he decided on was supremacy.
That was not to say that Lex was giving up on anything he already had - far from it. It was precisely because he didn't want to give up on anything that he went for supremacy. For a while he contemplated perfection, but it did not have the same feel to it.
In anything and everything that he wanted to do, he wanted absolute supremacy. To be absolutely sure this was exactly what he was thinking, he even checked a dictionary for the definition.
Supremacy was the state or condition of being superior to all in authority, power or status. Lex wanted supremacy in everything he desired to pursue.