This is the 8215th most frequent Catalan word.
deix
Trace, remnant, or hint.
In this example, 'deix' signifies a slight lingering sensation or taste, which is manifested as 'a hint of lemon' in the cake.
El pastís té un deix de llimona.
The cake has a hint of lemon.
In this sentence, 'deix' refers to a subtle lingering quality or tone, in this case, 'an ancient tone' found in the document.
Aquest document té un deix antic.
This document has an ancient tone.
Here, 'deix' represents a hint or trace of an emotion, specifically 'sadness,' perceived in her voice.