Is there a symbol for "Time Displacement" Does the "Time Displacement" property of a wave function have an associated symbol?


  Amplitude = $\hat U$
  
  Period = $T$
  
  Ordinary frequency = $f$
  
  Angular frequency = $ω$
  
  Phase = $ϕ$
  
  Time Displacement = ?


The term appears in my college lecture notes:
For this analogy assume $\alpha &gt; 0$.

The author of that text is simply using the term time displacement to mean the time it would take the lagging function to achieve the same $y$ value (displacement, field magnitude etc.) as the leading function. 

In that sense $\Delta t$ is not a bad choice for a symbol. Especially considering that distance displacement is commonly represented by the symbol $\Delta x$.
Physicists use $t$ for time, the variable, units second.