Unknown word; unattested (cp. corpus). Conjectural existence, given that a Quenya word for "flag" is known
("") and these two languages coexisted in diglossia.
Spurious Sindarin word as given by Yandex translate:
it is actually (English) "flag"
rendered in tengwar —
General Mode with ómatehtar (f+l+ag).
Encoding still unstable (Unicode: proposed 1997, SMP roadmapped;
CSUR: 2001 and 2008: ""; 1997: "").