On gloss:

jvisrbipmo
in sense "(Le Système international d'unités; International System of Units) Bureau international des poids et mesures"
 x_{1} is the BIPM (French: Bureau international des poids et mesures; English: International Bureau of Weights and Measures) designation/result/standard/code for topic x_{2} applied to specific case/individual/group/entity/idea/thing x_{3} according to rule/BIPM specification x_{4} published by/according to mandating organization x_{5} (default: BIPM)
On grammatical class:
 si
 erase the last Lojban word, treating nonLojban text as a single word.
In definition:
 cmavrsi
 x_{1} is the selma'o "SI".
In notes:
 vicma'o
 x_{1} is an eraser word
 kamre
 x_{1} is a x_{2} (li; number) of x_{3} in dimension/aspect x_{4} (default units)
 plankexu
 x_{1} is the elementary unit (quantum) of angular momentum/half of Planck's reduced constant [id est: hbar/2 = h/(4 pi)] expressed in units x_{2} (default: unitless/dimensionless and so that it is equal to 1) in paradigm/system/metaphysics/universe x_{3} (default: this, our actual, physical universe)