The thistle mistletoe formula is a pagan Norse Runic formula, involving several rhyming words ending in -istill (typically at least þistill and mistill; thistle and mistletoe). The formula is attested in around 15 variants from the Viking Age.
The Swedish Ledberg stone from Östergötland contains the formula. Following a standard memorial inscription, we read
ᚦᛘᚴ
þmk
᛬
:
ᛁᛁᛁ
iii
᛬
:
ᛋᛋᛋ
sss
᛬
:
ᛏᛏᛏ
ttt
᛬
:
ᛁᛁᛁ
iii
᛬
:
ᛚᛚᛚ
lll
᛬
:
When resolved becomes, in normalized Old Icelandic spelling:
þistill,
thistle,
mistill,
mistletoe,
kistill
casket
Likewise, the Danish Gørlev stone contains the exact same formula, along with a younger futhark rune-row.
The formula reaches its climax in a riddle in the legendary Icelandic Saga of Bósi and Herraud, where it reads (from manuscript AM. 586 4:0, transliterated into the Latin alphabet):
r.o.þ.k.m.u. iiiiii. ssssss. tttttt. iiiiii. llllll
Resolved and normalized, we get:
ristill,
plowshare,
eistill,
testicle,
þistill,
thistle,
kistill,
box/casket,
mistill,
mistletoe,
vistill
?
The meaning of the final word, uistil (vistill), is unclear.