Definition of "especial"

[...] this is of especial value in foggy weather.

1941 July, “The Why and the Wherefore: Inner and Outer Distant Signals”, in Railway Magazine, page 336

Starting from this base list, a number of databases were systematically searched for terms, with especial effort taken to discover the earliest attestation possible[.]

2018, James Lambert, “A multitude of ‘lishes’: The nomenclature of hybridity”, in English World-Wide‎, page 5

Only one modern picture was admitted, and that was a likeness of Constance, painted under her father's especial instructions.

1837, L[etitia] E[lizabeth] L[andon], “The Influence of the Dead”, in Ethel Churchill: Or, The Two Brides. […], volume II, London: Henry Colburn, […], page 270