Core dictionary (coreCIF) version 2.4.5
The number of reflections in the _refln_ list (not the _diffrn_refln_ list) that are significantly intense, satisfying the criterion specified by _reflns_threshold_expression. This may include Friedel-equivalent reflections (i.e. those which are symmetry-equivalent under the Laue symmetry but inequivalent under the crystal class) according to the nature of the structure and the procedures used. Special characteristics of the reflections included in the _refln_ list should be given in the item _reflns_special_details.
The permitted range is 0 -> infinity
Related item: _reflns_number_observed (alternate)