The most common and most likely answer to this crossword clue is the 8 letter word ERICSSON
I've seen this crossword clue in Independent
E
R
I
C
S
S
O
N
More clues leading to the result ERICSSON
Buddy explains!
The straight part
We know that "explorer (Leif Ericsson, Icelandic explorer of 11th century)" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case explorer (leif ericsson, icelandic explorer of 11th century) = ericsson.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.