On grammatical class:

boi
elidable terminator: terminate numeral or letteral string.
boi'e'u
mekso operator/function terminator (in Polish notation): inserts exactly enough "{boi}"'s consecutively so as to terminate the most recently uttered operator/function in a mekso expression

In definition:

bantu'asu
x1 is the language with ISO 639-3 code “tas” (Tay Boi).
cmavrboi
x1 is the selma'o "BOI".
ka'i zei sumtika
x1 is a part of Lojban text representing rule 'sumti' that has the only terminal 'KOhA #' or 'lerfu-string /BOI#/' in the formal grammar of the first edition of the book 'The Complete Lojban Language'.

In notes:

be'ei'oi
ternary mekso operator: x1th Bergelson multiplicative interval with exponents bounded from above by function x2 and with sequence of shifts x3, where exponents belong to set x4
fa'ai
mathematical ordered n-ary operator: (pointwise) functional left composition; X1 \circ X.
ja'oi
permutation cycle writer notation start
kau'ai
Microdigit-spanning endianness binary-toggle.
kau'au
Macrodigit-spanning endianness binary-toggle.
kei'ai
mekso style converter: elementwise application of operator
kei'au
mekso operator: finite result set derived from/on set A with/due to operator/function B under ordering of application C
noi'au
number/interpreted mathematical object non-restrictive clause
poi'au
number/interpreted mathematical object restrictive clause
sau'i
mekso n-ary operator: reciprocal of the sum of the reciprocal of each of X1, X2, ..., Xn (for any natural number n); 1/((1/X1) + (1/X.
se'u'o
selbri conversion question
slurume
x1 is a part of Lojban text representing rule 'free' according to the first edition of the book 'The Complete Lojban Language'.
terkanu
x1 is a part of Lojban text representing rule 'quantifier' according to the first edition of the book 'The Complete Lojban Language'.
ci zei mektika
x1 is a part of Lojban text representing rule 'operand-3' according to the first edition of the book 'The Complete Lojban Language'.
xa zei sumtika
x1 is a part of Lojban text representing rule 'sumti-6' according to the first edition of the book 'The Complete Lojban Language'.